2018年第12周小麦文献推荐（3.24） 这一周文献很多，值得一读的文献也有几篇。 1 Genome editing of bread wheat using biolistic delivery of CRISPR/Cas9 in vitro transcripts or ribonucleoproteins In recent years, CRISPR/Cas9 has emerged as a powerful tool for improving crop traits. Conventional plant genome editing mainly relies on plasmid-carrying cassettes delivered by Agrobacterium or particle bombardment. Here, we describe DNA-free editing of bread wheat by delivering in vitro transcripts (IVTs) or ribonucleoprotein complexes (RNPs) of CRISPR/Cas9 by particle bombardment. This protocol serves as an extension of our previously published protocol on genome editing in bread wheat using CRISPR/Cas9 plasmids delivered by particle bombardment. The methods we describe not only eliminate random integration of CRISPR/Cas9 into genomic DNA, but also reduce off-target effects. In this protocol extension article, we present detailed protocols for preparation of IVTs and RNPs; validation by PCR/restriction enzyme (RE) and next-generation sequencing; delivery by biolistics; and recovery of mutants and identification of mutants by pooling methods and Sanger sequencing. To use these protocols, researchers should have basic skills and experience in molecular biology and biolistic transformation. By using these protocols, plants edited without the use of any foreign DNA can be generated and identified within 9–11 weeks. 2 Yield and grain weight responses to post-anthesis increases in maximum temperature under field grown wheat as modified by nitrogen supply High-temperatures reduce yield of wheat and with global warming episodes of heat waves (only few days of high maximum temperatures) during grain filling will become more frequent. It has been recently reported that the magnitude of the yield penalties imposed by high temperatures under field conditions may interact with nitrogen (N) availability both in barley and maize. We determined, under field conditions, the penalties imposed by post-anthesis high-temperatures waves (increased maximum –but not minimum– temperatures during part of the grain filling period) on wheat yield under contrasting soil N supply during two consecutive years. The high temperature treatment was imposed for 10 d starting 10 d after anthesis by placing over the crops transparent polyethylene film (125 μm) mounted on wood structures of 1.5 m height above the ground. This high-temperature and the unheated controls were imposed on 5 modern and well adapted cultivars under contrasting N availabilities (376, 268 and 68 KgN ha−1). Averaged across N conditions, high-temperature treatments reduced yield by c . 1.5 Mg ha−1 (a loss of c . 17%) even though the treatment was rather mild in terms of different average temperature during grain filling. The magnitude of the loss was consistently shaped by the N condition in which the treatment was imposed: yield penalty produced by high-temperature increased from less than 1 to 2.6 Mg ha−1 (which represents losses from 10 to 25%) in parallel with the increased N supply. The penalties were related to both yield components (grain number and average grain weight) which also were more severely penalised under high than under low N supply. As episodes of high-temperature waves will become more frequent in the future the tools used to establish the needs of N fertilisation should be revised as the rates maximising yield (or gross margin) might induce higher sensitivities to these episodes. Also simulation models used to upscale physiological responses to regional or even global domains might need to be revised to include the effect of heat waves (which would be larger per °C increase than what is estimated from experiments increasing temperature during the whole day and over longer periods) as well as the interaction with N supply. 3 Identification and characterization of phenolic compounds extracted from barley husks by LC-MS and antioxidant activity in vitro Phenolic compounds were extracted from Tunisian barley husks obtained through a pearling process, by using two different extraction solvents: acid treatment with sulfuric acid and alkaline delignification with sodium hydroxide. Their antioxidant properties in vitro were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and butylated hydroxyanisole (BHA). Antioxidants composition was evaluated with LC-MS analysis. Findings suggest that the best yields of crude extracts with high level of phenolic compounds exhibiting strong antioxidant activities were found after pre-hydrolysis and delignification step of barley husks. The lowest average total phenolic content found was 763.665 mg/100 g, presenting an EC50 value of 0.93 g/L, four higher antioxidant levels than BHA (0.24 g/L). All extracted fractions showed high contents of p-coumaric acid (≥491.189 mg/100 g), trans-ferulic acid (≥501.475 mg/100 g) and syringic acid (≥192.228 mg/100 g). These results contribute to enhancing the value of barley husks as a good source of natural antioxidants, which serve as new functional food ingredients and dietary supplements. 4 Improving water use efficiency and grain yield of winter wheat by optimizing irrigations in the North China Plain Achieving the combination of high water use efficiency (WUE) and high yield is very important for the sustainable development of wheat production in the North China Plain (NCP). For this study, we investigated how to optimize timing of two irrigations to improve winter wheat grain yield and WUE under field conditions. No-irrigation after sowing (W0) as a control, and six irrigation treatments as follows: irrigation of 75 mm each at late tillering and booting (TB), at late tillering and anthesis (TA); at late tillering and medium milk (TM), at jointing and anthesis (JA), at jointing and medium milk (JM) and at booting and medium milk (BM). Experiments were conducted between the 2014–2016 growing seasons. In all the treatments, JA achieved the highest grain yield (9,267.6 kg ha−1) and WUE (20.2 kg ha−1 mm−1). Compared with TB, TA and TM, JA coordinated pre- and post-anthesis water use, reduced pre-anthesis and total evapotranspiration (ET), and increased post-anthesis water use amount and ratio; JA reduced biomass at anthesis, but optimized allocation of assimilation, increased spike partitioning index and maintained high fruiting efficiency, and thus obtained the highest grain number per m2(GN, 23.7 103 m−2). Meanwhile, JA optimized crop characteristics with appropriate leaf area index (LAI), delayed leaf senescence, extended grain filling duration by 1–3 days, then increased biomass post-anthesis and harvest index (HI). Compared with JM and BM, JA increased GN, biomass post-anthesis and grain yield as well. These results demonstrated that irrigation at jointing and anthesis could improve grain yield and WUE by increasing biomass post-anthesis, HI and GN. Therefore, we propose that under adequate soil moisture conditions before sowing, two irrigations at jointing and anthesis with 150 mm irrigation amount is the optimal limited irrigation practice for wheat production in NCP. 5 Integrated agronomic practices management improve yield and nitrogen balance in double cropping of winter wheat-summer maize 6 Tillage and residue management for long-term wheat-maize cropping in the North China Plain: I. Crop yield and integrated soil fertility index Conservation tillage has been gaining increasing recognition for its role in improving soil quality and maintaining agricultural sustainability. This is the first in a series of papers describing the impacts of reduced/no-tillage with and without residue based on the field experiment in the North China Plain. The experiment was established in 2006 on a sandy loam soil and involved a winter wheat-summer maize rotation system per year. The objective of this study was to investigate the impacts of different conservation tillage systems on crop yield and soil fertility that was quantified by a minimum data set and integrated index. Soil samples were collected since 2011, and the stocks of soil organic matter (SOM), total nitrogen (TN), alkali-hydrolyzale nitrogen (AN), total phosphorus (TP), available phosphorus (AP), total potassium (TK) and available potassium (AK) were measured for each year as well as soil aggregates were fractionated for 2016. Compared to continuous tillage, the reduced/no-tillage, regardless of residue, significantly increased the macroaggregate mass and soil nutrient stocks at the 0–10 cm depth, while further improvements in these soil attributes apart from TK were observed at the 0–10 and 10–20 cm depths for residue returning relative to residue removing. The accumulations of soil nutrients were closely related to soil macroaggregation. The path analysis revealed that TN was the most important soil attribute to directly determine wheat and maize yields while other soil attributes apart for TK primarily made indirect contributions to the yields. The first two factors extracted using 8 soil attributes through factor analysis were selected as the integrated indicators for the minimum data set, and their integrated score was calculated to quantify soil fertility. It was found that reduced/no-tillage did not improved soil fertility at the 0–20 cm depth. Consequently, an average 6.9% decrease in wheat yield across all years was observed under no-tillage while reduced tillage only increased the yield in the first two years in a periodic reduced tillage event. No significant difference was observed for the mean maize yield among the three tillage regimes averaged across all years and residue managements. Wheat and maize yields were significantly correlated with the integrated score for soil fertility, and thus significant increases in grain yields of wheat and maize were observed for residue returning. It can be concluded that grain yields of wheat and maize within a given residue management practice were not significantly higher for reduced/no-tillage than continuous tillage, regardless of the effects of tillage on aggregates and soil nutrients. 7 Wheat miR9678 Affects Seed Germination by Generating Phased siRNAs and Modulating Abscisic Acid/Gibberellin Signaling Seed germination is important for grain yield and quality and rapid, near-simultaneous germination helps in cultivation; however, cultivars that germinate too readily can undergo pre-harvest sprouting (PHS), which causes substantial losses in areas that tend to get rain around harvest time. Moreover, our knowledge of mechanisms regulating seed germination in wheat (Triticum aestivum) remains limited. In this study, we analyzed function of a wheat-specific microRNA 9678 (miR9678), which is specifically expressed in the scutellum of developing and germinating seeds. Overexpression of miR9678 delayed germination and improved resistance to PHS in wheat through reducing bioactive gibberellins (GAs) levels; miR9678 silencing enhanced germination rates. We provide evidence that miR9678 targets a long non-coding RNA(WSGAR)and triggers the generation of phased siRNA which play a role in the delay of seed germination. Finally, we found that abscisic acid (ABA) signaling proteins bind the promoter of miR9678 precursor and activate its expression, indicating that miR9678 affects germination by modulating the GA/ABA signaling. 8 Effect of sowing time and seeding rate on yield components and water use efficiency of winter wheat by regulating the growth redundancy and physiological traits of root and shoot 9 The activity of superoxide dismutases (SODs) at the early stages of wheat deetiolation Unbound tetrapyrroles, i . e . protochlorophyllide (Pchlide), chlorophyllide and chlorophylls, bring the risk of reactive oxygen species (ROS) being generated in the initial stages of angiosperm deetiolation due to inefficient usage of the excitation energy for photosynthetic photochemistry. We analyzed the activity of superoxide dismutases (SODs) in etiolated wheat ( Triticum aestivum ) leaves and at the beginning of their deetiolation. Mn-SOD and three isoforms of Cu/Zn-SODs were identified both in etiolated and greening leaves of T . aestivum . Two Cu/Zn-SODs, denoted as II and III, were found in plastids. The activity of plastidic Cu/Zn-SOD isoforms as well as that of Mn-SOD correlated with cell aging along a monocot leaf, being the highest at leaf tips. Moreover, a high Pchlide content at leaf tips was observed. No correlation between SOD activity and the accumulation of photoactive Pchlide, i . e . Pchlide bound into ternary Pchlide:Pchlide oxidoreductase:NADPH complexes was found. Cu/Zn-SOD I showed the highest activity at the leaf base. A flash of light induced photoreduction of the photoactive Pchlide to chlorophyllide as well as an increase in all the SODs activity which occurred in a minute time-scale. In the case of seedlings that were deetiolated under continuous light of moderate intensity (100 μmol photons m-2 s-1), only some fluctuations in plastidic Cu/Zn-SODs and Mn-SOD within the first four hours of greening were noticed. The activity of SODs is discussed with respect to the assembly of tetrapyrroles within pigment-protein complexes, monitored by fluorescence spectroscopy at 77 K. 10 Fungicide and cultivar management of leaf spot diseases of winter wheat in western Canada A complex of leaf spotting diseases are frequently observed on winter wheat in western Canada; however, there are few studies indicating varietal differences in reaction to these diseases or the benefit of fungicide application. To determine the benefit of varietal improvement, and multiple fungicide treatments and application timings, field experiments were conducted at six site-years in western Canada. Two cultivars varying in reaction to leaf spot diseases were used in combination with fungicide treatments. Disease severity ranged from trace to 64% of the combined flag and penultimate leaf area diseased, differed between cultivars, and was reduced from the check by some fungicide treatments. Yield improvement by fungicide treatment varied from 3.3 to 13.2% greater than the non-treated check. At two site-years, the split application of two half rates of fungicide resulted in the greatest yield; however, in both cases the yield benefit did not differ from a single application at the flag leaf growth stage. Cultivar selection and fungicide use under environments conducive to disease are beneficial components of an integrated leaf spot disease management program for winter wheat in western Canada. 11 First report of Fusarium pseudograminearum causing crown rot of wheat in Europe 12 Long-Term Irrigation Affects the Dynamics and Activity of the Wheat Rhizosphere Microbiome 13 Proteomic analysis of melatonin-mediated osmotic tolerance by improving energy metabolism and autophagy in wheat ( Triticum aestivum L.) Melatonin is known to play multiple roles in plant abiotic stress tolerance. However, its role in wheat has been rarely investigated. In this study, 25% polyethylene glycol 6000 (PEG 6000) was used to simulate osmotic stress, and wheat seeds and seedlings were treated with different concentrations of melatonin under PEG stress. Isobaric tag for relative and absolute quantification (iTRAQ)-based proteomic techniques were used to identify the differentially accumulated proteins from melatonin-treated and non-treated seedlings. Seeding priming with melatonin significantly increased the germination rate, coleoptile length, and primary root number of wheat under PEG stress, as well as the fresh weight, dry weight, and water content of wheat seedlings. Under PEG stress, melatonin significantly improved reactive oxygen species homeostasis, as revealed by lower H2O2 and O 2 · content; and the expression of antioxidant enzymes at the transcription and translation levels was increased. Melatonin maintained seedling growth by improving photosynthetic rates and instantaneous and intrinsic water use efficiencies, as well as carbon fixation and starch synthesis at the protein level. Melatonin treatment significantly affected the expression of glycolytic proteins, including fructose-1,6-bisphosphate aldolase, hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and enolase, and remarkably increased the expression of the nicotinamide adenine dinucleotide transporter and nicotinamide adenine dinucleotide binding protein, thereby indirectly modulating electron transport in the respiratory chain. This indicated that melatonin improved energy production in PEG-stressed seedlings. Further, melatonin played a regulatory role in autophagy, protease expression, and ubiquitin-mediated protein degradation by significantly upregulating rab-related protein, fused signal recognition particle receptor, aspartyl protease, serine protease, ubiquitin-fold modifier 1, and ubiquitin at the mRNA or protein level. These findings suggested that melatonin might activate a metabolic cascade related to autophagy under PEG stress in wheat seedlings. 14 The wheat TabZIP2 transcription factor is activated by the nutrient starvation-responsive SnRK3/CIPK protein kinase Basic leucine zipper (bZIP) transcription factors (TFs) play key roles in the regulation of grain development and plant responses to abiotic stresses. We investigated the role and molecular mechanisms of function of the TabZIP2 gene isolated from drought-stressed wheat plants. Molecular characterisation of TabZIP2 and derived protein included analyses of gene expression and its target promoter, and the influence of interacting partners on the target promoter activation. Two interacting partners of TabZIP2, the 14-3-3 protein, TaWIN1 and the bZIP transcription factor TaABI5L, were identified in a Y2H screen. We established that under elevated ABA levels the activity of TabZIP2 was negatively regulated by the TaWIN1 protein and positively regulated by the SnRK3/CIPK protein kinase WPK4, reported previously to be responsive to nutrient starvation. The physical interaction between the TaWIN1 and the WPK4 was detected. We also compared the influence of homo- and hetero-dimerisation of TabZIP2 and TaABI5L on DNA binding. TabZIP2 gene functional analyses were performed using drought-inducible overexpression of TabZIP2 in transgenic wheat. Transgenic plants grown under moderate drought during flowering, were smaller than control plants, and had fewer spikes and seeds per plant. However, a single seed weight was increased compared to single seed weights of control plants in three of four evaluated transgenic lines. The observed phenotypes of transgenic plants and the regulation of TabZIP2 activity by nutrient starvation-responsive WPK4, suggest that the TabZIP2 could be the part of a signalling pathway, which controls the rearrangement of carbohydrate and nutrient flows in plant organs in response to drought. 15 Characterization of Pm59 , a novel powdery mildew resistance gene in Afghanistan wheat landrace PI 181356 Powdery mildew, caused by Blumeria graminis f. sp. tritici ( Bgt ), is an important foliar disease of wheat worldwide. In the Great Plains of the USA, Bgt isolates virulent to widely used powdery mildew resistance genes, such as Pm3a , were previously identified. The objectives of this study were to characterize the powdery mildew resistance gene in Afghanistan landrace PI 181356, which exhibited high resistance to Bgt isolates collected in southern Great Plains, and identify molecular markers for marker-assisted selection. An F2 population and F2:3 lines derived from a cross between PI 181356 and OK1059060-126135-3 were used in this study. Genetic analysis indicated that PI 181356 carries a single dominant gene, designated Pm59 , in the terminal region of the long arm of chromosome 7A. Pm59 was mapped to an interval between sequence tag site (STS) markers Xmag1759 and Xmag1714 with genetic distances of 0.4 cM distal to Xmag1759 and 5.7 cM proximal to Xmag1714. Physical mapping suggested that Pm59 is in the distal bin 7AL 0.99–1.00. Pm59 is a novel powdery mildew resistance gene, and confers resistance to Bgt isolates collected from the Great Plains and the state of Montana. Therefore, Pm59 can be used to breed powdery mildew-resistant cultivars in these regions. Xmag1759 is ideal for marker-assisted selection of Pm59 in wheat breeding. 16 Characterisation and mapping of adult plant stripe rust resistance in wheat accession Aus27284 Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is among the most important constraints to global wheat production. The identification and characterisation of new sources of host plant resistance enrich the gene pool and underpin deployment of resistance gene pyramids in new cultivars. Aus27284 exhibited resistance at the adult plant stage against predominant Pst pathotypes and was crossed with a susceptible genotype Avocet S. A recombinant inbred line (RIL) population comprising 121 lines was developed and tested in the field at three locations in 2016 and two in 2017 crop seasons. Monogenic segregation for adult plant stripe rust response was observed among the Aus27284/Avocet S RIL population and the underlying locus was temporarily designated YrAW11 . Bulked-segregant analysis using the Infinium iSelect 90K SNP wheat array placed YrAW11 in chromosome 3B. Kompetitive allele specific PCR (KASP) primers were designed for the linked SNPs and YrAW11 was flanked by KASP_65624 and KASP_53292 (3 cM) proximally and KASP_53113 (4.9 cM) distally. A partial linkage map of the genomic region carrying YrAW11 comprised nine KASP and two SSR markers. The physical position of KASP markers in the pseudomolecule of chromosome 3B placed YrAW11 in the long arm and the location of markers gwm108 and gwm376 in the deletion bin 3BL2-0.22 supported this conclusion. As no other stripe rust resistance locus has been reported in chromosome 3BL, YrAW11 was formally designated Yr80 . Marker KASP_ 53113 was polymorphic among 94% of 81 Australian wheat cultivars used for validation. 17 Systematic analysis of the lysine malonylome in common wheat In total, 342 lysine malonylated sites were identified in 233 proteins. Bioinformatics analysis showed that the frequency of arginine (R) in position + 1 was highest, and a modification motif, KmaR, was identified. The malonylated proteins were located in multiple subcellular compartments, especially in the cytosol (45%) and chloroplast (30%). The identified proteins were found to be involved in diverse pathways, such as carbon metabolism, the Calvin cycle, and the biosynthesis of amino acids, suggesting an important role for lysine malonylation in these processes. Protein interaction network analysis revealed eight highly interconnected clusters of malonylated proteins, and 137 malonylated proteins were mapped to the protein network database. Moreover, five proteins were simultaneously modified by lysine malonylation, acetylation and succinylation, suggesting that these three PTMs may coordinately regulate the function of many proteins in common wheat. 18 The Impact of Phosphorus Supply on Selenium Uptake During Hydroponics Experiment of Winter Wheat ( Triticum aestivum ) in China Selenium (Se) is a necessary trace element for humans and animals, and Se fertilization is an efficient way to increase Se concentration in the edible parts of crops, thus enhance the beneficiary effects of Se in human and animal health. Due to the similarity of physical and chemical properties between phosphate ( ) and selenite ( ), phosphorus (P) supply often significantly impacts the absorption of Se in plants, but little is known about how P supply influences the subcellular distribution and chemical forms of Se. In this study, the effects of P supply on subcellular distribution and chemical forms of Se in winter wheat were investigated in a hydroponic trial with medium Se level (0.1 mg Se L-1). P was applied with three concentrations (0.31, 3.1, and 31 mg P L-1) in the experiment. The results showed that increasing P supply significantly decreased the concentration and accumulation of Se in the roots, stems, and leaves of winter wheat. An increase in P supply significantly inhibited Se accumulation in the root cell wall, but enhanced Se distribution in the organelles and soluble fraction of root cells. These findings suggest that increased P supply inhibited the root-to-shoot transport of Se. An increase in P supply enhanced Se accumulation in the cell wall of plant stems (both apical and axillary stem) and cell organelles of plants leaves, but inhibited Se distribution in the soluble fraction of stems and leaves. This suggests that P supply enhances Se transportation across the cell membrane in shoots of winter wheat. In addition, increased P supply also altered the chemical forms of Se in tissues of winter wheat. These findings will help in understanding of the regulation grain Se accumulation and provide a practical way to enhance Se intake for humans inform Se-enriched grains. 19 Pm21 from Haynaldia villosa Encodes a CC-NBS-LRR that Confers Powdery Mildew Resistance in Wheat 20 Pm21 , encoding a typical CC-NBS-LRR protein, confers broad-spectrum resistance to wheat powdery mildew disease 21 Genetic relationship of diploid wheat ( Triticum spp.) species assessed by SSR markers Genetic diversity of 139 accessions of diploid Triticum species including Triticum urartu , Triticum boeoticum and Triticum monococcum was studied using 11 SSR (simple sequence repeats) markers. A total of 111 alleles with an average of 10 alleles per locus were detected. The polymorphism information content (PIC) of each SSR marker ranged from 0.30 to 0.90 with an average value of 0.62. Among the three Triticum species T. urartu had the highest number of total alleles (Na = 81), private alleles (Npa = 15) and showed higher genetic diversity (Hex = 0.58; PIC = 0.54). The genotypes from Turkey exhibited the highest genetic diversity (PIC = 0.6), while the least diversity was observed among 4 Georgian accessions (PIC = 0.11). Cluster analysis was able to distinguish 139 wheat accessions at the species level. The highest genetic similarity (GS) was noted between T. boeticum and T. monococcum (GS = 0.84), and the lowest between T. urartu and T. monococcum (GS = 0.46). The grouping pattern of the PCoA analysis corresponded with cluster analysis. No significant differences were found in clustering of T. urartu and T. monococcum accessions with respect to their geographic regions, while within T. boeoticum species, accessions from Iran were somewhat associated with their geographical origin and clustered as a close and separate group. The results from our study demonstrated that SSR markers were good enough for further genetic diversity analysis in einkorn wheat species. 22 A new player in race-specific resistance 23 Complex regulation of the TaMyc1 gene expression in wheat grain synthesizing anthocyanin pigments The wheat TaMyc1 gene encodes for transcriptional factor (TF) with bHLH domain. The gene is expressed in purple wheat grains and activates transcription of the anthocyanin biosynthesis structural genes. To reveal the features of TaMyc1 regulation in wheat pericarp transcription start sites (TSS) were identified by 5′ RACE mean and translation efficiency was predicted by in silico methods. Three alternative transcript variants of TaMyc1 differing by 5′ leader sequence only were identified in purple pericarp. The three transcripts are generated from distinct TATA boxes and thereby are differed by TSS. Two transcripts ( TaMyc1a, -b ) have identical initiation AUG codons that lead to the TaMYC1 regulatory protein with bHLH domain. However because of different stability of secondary structures predicted in 5′ leader the two transcripts might be translated with different efficiency. The third transcript is assumed to be not effectively translated. qRT-PCR and colonies counting were applied to assess contribution each of the transcripts to total TaMyc1 gene transcription level. TaMyc1c has the lowest contribution ( ca . 16%), whereas the others two transcripts contribute equally ( ca . 42%) to total TaMyc1 expression level. The role of the tree mRNA isoforms transcribed in one tissue is discussed. 24 Exploiting the Rht portfolio for hybrid wheat breeding Plant height is an important trait in wheat line breeding, but is of even greater importance in hybrid wheat breeding. Here, the height of the female and male parental lines must be controlled and adjusted relative to each other to maximize hybrid seed production. In addition, the height of the resulting hybrids must be fine-tuned to meet the specific requirements of the farmers in the target regions. Moreover, this must be achieved without adversely impacting traits relevant for hybrid seed production. In this study, we explored Reduced height ( Rht ) loci effective in elite wheat and exploited their utilization for hybrid wheat breeding. We performed association mapping in a panel of 1705 wheat hybrids and their 225 parental lines, which besides the Rht - B1 and Rht - D1 loci revealed Rht24 as a major QTL for plant height. Furthermore, we found that the Rht - 1 loci also reduce anther extrusion and thus cross-pollination ability, whereas Rht24 appeared to have no adverse effect on this trait. Our results suggest different haplotypes of the three Rht loci to be used in the female or male pool of a hybrid breeding program, but also show that in general, plant height is a quantitative trait controlled by numerous small-effect QTL. Consequently, marker-assisted selection for the major Rht loci must be complemented by phenotypic selection to achieve the desired height in the female and male parents as well as in the wheat hybrids. 25 Molecular Cytogenetic Characterization of New Wheat— Dasypyrum breviaristatum Introgression Lines for Improving Grain Quality of Wheat As an important relative of wheat ( Triticum aestivum L), Dasypyrum breviaristatum contains novel high molecular weight glutenin subunits (HMW-GSs) encoded by Glu-1Vb genes. We identified new wheat— D. breviaristatum chromosome introgression lines including chromosomes 1Vb and 1VbL.5VbL by fluorescence in situ hybridization (FISH) combined with molecular markers. We found that chromosome changes occurred in the wheat— D. breviaristatum introgression lines and particularly induced the deletion of 5BS terminal repeats and formation of a new type of 5B-7B reciprocal translocation. The results imply that the D. breviaristatum chromosome 1Vb may contain genes which induce chromosomal recombination in wheat background. Ten putative high molecular weight glutenin subunit (HMW-GS) genes from D. breviaristatum and wheat— D. breviaristatum introgression lines were isolated. The lengths of the HMW-GS genes in Dasypyrum were significantly shorter than typical HMW-GS of common wheat. A new y-type HMW-GS gene, named Glu-Vb1y , was characterized in wheat— D. breviaristatum 1Vb introgression lines. The new wheat— D. breviaristatum germplasm displayed reduced plant height, increased tillers and superior grain protein and gluten contents, improved gluten performance index. The results showed considerable potential for utilization of D. breviaristatum chromosome 1Vb segments in future wheat improvement. 26 Wheat ear counting in-field conditions: high throughput and low-cost approach using RGB images The results demonstrate high success rate (higher than 90%) between the algorithm counts and the manual (image-based) ear counts, and precision, with a low standard deviation (around 5%). The relationships between algorithm ear counts and grain yield was also significant and greater than the correlation with manual (field-based) ear counts. In this approach, results demonstrate that automatic ear counting performed on data captured around anthesis correlated better with grain yield than with images captured at later stages when the low performance of ear counting at late grain filling stages was associated with the loss of contrast between canopy and ears. 27 Dynamics of Floret Initiation/Death Determining Spike Fertility in Wheat as Affected by Ppd Genes under Field Conditions As wheat yield is linearly related to grain number, understanding the physiological determinants of the number of fertile florets based on floret development dynamics due to the role of the particular genes is relevant. The effects of photoperiod genes on dynamics of floret development are largely ignored. Field experiments were carried out to (i) characterize the dynamics of floret primordia initiation and degeneration and (ii) to determine which are the most critical traits of such dynamics in establishing genotypic differences in the number of fertile florets at anthesis in near isogenic lines (NILs) carrying photoperiod insensitive alleles. Results varied in magnitude between the two growing seasons, but in general introgression of Ppd-1a alleles reduced the number of fertile florets. The actual effect was affected not only by the genome and the doses but also by the source of the alleles. Differences in the number of fertile florets were mainly explained by differences in the floret generation/degeneration dynamics and in most cases associated with floret survival. Manipulating photoperiod insensitivity, unquestionably useful for changing flowering time, may reduce spike fertility but much less than proportionally to the change in duration of development, as the insensitivity alleles did increase the rate of floret development. 28 Rht18 Semi-Dwarfism in Wheat is Due to Increased Expression of GA 2-oxidaseA9 and Lower GA Content Semi-dwarfing genes have contributed to major yield increases in crop species by reducing height, improving lodging resistance, and partitioning more assimilates to grain growth. In wheat, the Rht18 semi-dwarfing gene was identified and deployed in durum wheat before it was transferred into bread wheat where it was shown to have agronomic potential. Rht18, a dominant and gibberellin (GA) responsive mutant, is genetically and functionally distinct from the widely used GA insensitive semi-dwarfing genes Rht-B1b and Rht-D1b. In this study, the Rht18 gene was identified by mutagenizing the semi-dwarf durum cultivar Icaro (Rht18) and generating mutants with a range of tall phenotypes. Isolating and sequencing chromosome 6A of these 'overgrowth' mutants showed that they contained independent mutations in the coding region of GA2oxA9, a gene predicted to encode a GA 2-oxidase that metabolises GA biosynthetic intermediates into inactive products, thereby lowering the amount of bioactive GA (GA1). Functional analysis of the GA2oxA9 protein demonstrated conversion of the intermediate GA12 to the inactive metabolite GA110. Analysis of transcript abundance and GA content showed that the expression of GA 2-oxA9 was higher, and the GA content lower, in Rht18 compared with its tall parent. These data indicate that the increased expression of GA2oxA9 in Rht18 results in a reduction of both bioactive GA content and plant height. This study describes a height reducing mechanism that can generate new genetic diversity for semi-dwarfism in wheat by combining increased expression with mutations of specific amino acid residues in the GA2oxA9 gene. 29 Photosynthetic and ascorbate-glutathione metabolism in the flag leaves as compared to spikes under drought stress of winter wheat (Triticum aestivum L.). Ascorbate-glutathione (ASA-GSH) cycle is a major pathway of H2O2 scavenging and an effective mechanism of detoxification in plants. The differences in photosynthesis, chlorophyll content (Chl), relative water content (RWC), antioxidants and antioxidative enzyme activities involved in ASA-GSH metabolism were measured between the flag leaves and spike bracts (glumes and lemmas) during grain filling under drought stress. The expression of APX1, GRC1, DHAR, MDHAR, GPX1, and GS3 in ASA-GSH cycle was also measured. Compared with the flag leaves, the spike bracts exhibited stable net photosynthetic rate (PN) and chlorophyll content (Chl), a lower accumulation of reactive oxygen species (ROS), and more enhanced percentages of antioxidant enzyme activities and key enzymes gene transcription levels involved in ASA-GSH metabolism during the grain-filling stage under drought conditions. This could be the reasonable explanation for the more stable photosynthetic capacity in spikes, and the glumes and lemmas senesced later than the flag leaves at the late grain-filling stage. Also, the function of ASA-GSH cycle could not be ignored in alleviating oxidative damage by scavenging more excess ROS in spikes under drought stress. 30 Proteomic analysis of melatonin-mediated osmotic tolerance by improving energy metabolism and autophagy in wheat (Triticum aestivum L.). Melatonin is known to play multiple roles in plant abiotic stress tolerance. However, its role in wheat has been rarely investigated. In this study, 25% polyethylene glycol 6000 (PEG 6000) was used to simulate osmotic stress, and wheat seeds and seedlings were treated with different concentrations of melatonin under PEG stress. Isobaric tag for relative and absolute quantification (iTRAQ)-based proteomic techniques were used to identify the differentially accumulated proteins from melatonin-treated and non-treated seedlings. Seeding priming with melatonin significantly increased the germination rate, coleoptile length, and primary root number of wheat under PEG stress, as well as the fresh weight, dry weight, and water content of wheat seedlings. Under PEG stress, melatonin significantly improved reactive oxygen species homeostasis, as revealed by lower H2O2 and O 2 · content; and the expression of antioxidant enzymes at the transcription and translation levels was increased. Melatonin maintained seedling growth by improving photosynthetic rates and instantaneous and intrinsic water use efficiencies, as well as carbon fixation and starch synthesis at the protein level. Melatonin treatment significantly affected the expression of glycolytic proteins, including fructose-1,6-bisphosphate aldolase, hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and enolase, and remarkably increased the expression of the nicotinamide adenine dinucleotide transporter and nicotinamide adenine dinucleotide binding protein, thereby indirectly modulating electron transport in the respiratory chain. This indicated that melatonin improved energy production in PEG-stressed seedlings. Further, melatonin played a regulatory role in autophagy, protease expression, and ubiquitin-mediated protein degradation by significantly upregulating rab-related protein, fused signal recognition particle receptor, aspartyl protease, serine protease, ubiquitin-fold modifier 1, and ubiquitin at the mRNA or protein level. These findings suggested that melatonin might activate a metabolic cascade related to autophagy under PEG stress in wheat seedlings. 31 Analysis of the functions of TaGW2 homoeologs in wheat grain weight and protein content traits GW2 is emerging as a key genetic determinant of grain weight in cereal crops, and has three homoeologs (TaGW2-A1, -B1 and -D1) in hexaploid common wheat (Triticum aestivum L.). Here, by analyzing the gene editing mutants lacking one (B1 or D1), two (B1 and D1) or all three (A1, B1 and D1) homoeologs of TaGW2, several insights are gained into the functions of TaGW2-B1 and -D1 in common wheat grain traits. First, both TaGW2-B1 and -D1 affect thousand grain weight (TGW) through influencing grain width and length, but the effect conferred by TaGW2-B1 is stronger than that by TaGW2-D1. Second, there exists functional interaction between TaGW2 homoeologs because the TGW increase shown by a double mutant (lacking B1 and D1) was substantially larger than that by their single mutants. Third, both TaGW2-B1 and -D1 modulate cell number and length in the outer pericarp of developing grains, with TaGW2-B1 being more potent. Finally, TaGW2 homoeologs also affect grain protein content (GPC) as this parameter was generally increased in the mutants, especially in the lines lacking two or three homoeologs. Consistent with this finding, two wheat end-use quality related parameters, flour protein content and gluten strength, were considerably elevated in the mutants. Collectively, our data shed light on functional difference and additive interaction of TaGW2 homoeologs in the genetic control of grain weight and protein content traits in common wheat, which may accelerate further research on this important gene and its application in wheat improvement. This article is protected by copyright. All rights reserved. 32 Dynamics of Leaf and Spikelet Primordia Initiation in Wheat as Affected by Ppd-1a Alleles under Field Conditions Wheat adaptation is affected by Ppd genes, but the role of these alleles on the rates of leaf and spikelet initiation has not been properly analysed. Twelve near isogenic lines (NILs) combining Ppd-1a alleles from different donors introgressed in A, B and/or D genomes were tested under field conditions during two growing seasons together with the wild type, Paragon. Leaf initiation rate was unaffected by Ppd-1a alleles so final leaf number (FLN) was reduced in parallel with reductions in the duration of vegetative phase. Spikelet primordia initiation was accelerated and consequently the effect on spikelets per spike was less than proportional to the effect on the duration of spikelet initiation. The magnitude of these effects on spikelet-plastochron depended on the doses of Ppd-1 homoeoalleles and the specific insensitivity alleles carried. Double ridge was consistently later than floral initiation but the difference between them was not affected by Ppd-1a alleles. These findings open potential for selecting best combinations from the Ppd-1 homoeoallelic series for manipulating adaptation considering particular effects on spikelet number. 33 Molecular Mapping of Fusarium Head Blight Resistance in the Spring Wheat Line ND2710. ND2710 is a hard red spring wheat line with a very high level of resistance to Fusarium head blight (FHB). It was selected from the progeny of a cross between ND2603 (an advanced breeding line derived from the Sumai 3/Wheaton cross) and Grandin (a spring wheat cultivar). The FHB resistance of ND2710 is presumably derived from Sumai 3 since the other parents Grandin and Wheaton are very susceptible to FHB. To identify and map the quantitative trait loci (QTL) for FHB resistance in ND2710, we developed a mapping population consisting of 233 recombinant inbred lines (RILs) from the cross between ND2710 and the spring wheat cultivar 'Bobwhite'. These RILs along with their parents and checks were evaluated for reactions to FHB in three greenhouse experiments and one field experiment during 2013 to 2014. The population was also genotyped with the wheat 90K SNP iSelect assay, and a genetic linkage map was developed with 1373 non-co-segregating SNP markers, which were distributed on all 21 wheat chromosomes spanning 914.98 cM of genetic distance. Genetic analyses using both phenotypic and genotypic data identified one major QTL (Qfhb.ndwp-3B) on the short arm of chromosome 3B, explaining up to 20% of the phenotypic variation in all experiments, and three minor QTL (Qfhb.ndwp-6B, Qfhb.ndwp-2A, and Qfhb.ndwp-6A) on 6B, 2A, and 6A, respectively. The three minor QTL explained 5 to 12% phenotypic variation in at least two experiments, except for Qfhb.ndwp-2A, which was only detected in the field experiment. Qfhb.ndwp-3B and Qfhb.ndwp-6B were mapped to the genomic regions containing Fhb1 and Fhb2, respectively, confirming that they were originated from Sumai 3. The additive effect of the major and minor QTL may contribute to the high level of FHB resistance in ND2710. The SNP markers closely linked to the FHB resistance QTL will be useful for marker-assisted selection of FHB resistance in wheat breeding programs. 34 Characterization of an Integrated Active Glu-1Ay Allele in Common Wheat from Wild Emmer and Its Potential Role in Flour Improvement. Glu-1Ay , one of six genes encoding a high molecular weight glutenin subunit (HMW-GS), is frequently silenced in hexaploid common wheat. Here, an active allele of Glu-1Ay was integrated from wild emmer wheat ( Triticum turgidum ssp. dicoccoides ) accession D97 into the common wheat ( Triticum aestivum ) cultivar Chuannong 16 via the repeated self-fertilization of the pentaploid interspecific hybrid, culminating in the selection of a line TaAy7-40 shown to express the wild emmer Glu-1Ay allele. The open reading frame of this allele was a 1830 bp long sequence, demonstrated by its heterologous expression in Escherichia coli to encode a 608-residue polypeptide. Its nucleotide sequence was 99.2% identical to that of the sequence within the wild emmer parent. The TaAy7-40 introgression line containing the active Glu-1Ay allele showed higher protein content, higher sodium dodecyl sulfate (SDS) sedimentation value, higher content of wet gluten in the flour, higher grain weight, and bigger grain size than Chuannong 16. The end-use quality parameters of the TaAy7-40 were superior to those of the medium gluten common wheat cultivars Mianmai 37 and Neimai 9. Thus, the active Glu-1Ay allele might be of potential value in breeding programs designed to improve wheat flour quality. 35 Systematic analysis of the lysine malonylome in common wheat In total, 342 lysine malonylated sites were identified in 233 proteins. Bioinformatics analysis showed that the frequency of arginine (R) in position + 1 was highest, and a modification motif, KmaR, was identified. The malonylated proteins were located in multiple subcellular compartments, especially in the cytosol (45%) and chloroplast (30%). The identified proteins were found to be involved in diverse pathways, such as carbon metabolism, the Calvin cycle, and the biosynthesis of amino acids, suggesting an important role for lysine malonylation in these processes. Protein interaction network analysis revealed eight highly interconnected clusters of malonylated proteins, and 137 malonylated proteins were mapped to the protein network database. Moreover, five proteins were simultaneously modified by lysine malonylation, acetylation and succinylation, suggesting that these three PTMs may coordinately regulate the function of many proteins in common wheat. 36 Genome-Wide Identification and Characterization of Long Non-Coding RNA in Wheat Roots in Response to Ca2+ Channel Blocker It remains unclear whether plant lncRNAs are responsive to Ca2+-channel blocking. When using the Ca2+-channel blocker, LaCl3, to treat germinated wheat seeds for 24 h, we found that both root length and mitosis were inhibited in the LaCl3-treated groups. The effect of the Ca2+-channel blocker was verified in three ways: a cytdecrease detected using Fluo-3/AM staining, a decrease in the Ca content measured using inductively coupled plasma mass spectrometry, and an inhibition of Ca2+influx detected using Non-invasive Micro-test Technology. Genome-wide high throughput RNA-seq and bioinformatical methods were used to identify lncRNAs, and found 177 differentially expressed lncRNAs that might be in responsive to Ca2+-channel blocking. Among these, 108 were up-regulated and 69 were down-regulated. The validity of identified lncRNAs data from RNA-seq was verified using qPCR. GO and KEGG analysis indicated that a number of lncRNAs might be involved in diverse biological processes upon Ca2+-channel blocking. Further GO analysis showed that 23 lncRNAs might play roles as transcription factor (TF); Moreover, eight lncRNAs might participate in cell cycle regulation, and their relative expressions were detected using qPCR. This study also provides diverse data on wheat lncRNAs that can deepen our understanding of the function and regulatory mechanism of Ca2+-channel blocking in plants. 36 First report of Fusarium pseudograminearum causing crown rot of wheat in Europe
2018年第10周小麦文献推荐（3.11） 正式开始前，先说说我们前面举办的一个答题赢话费活动，前几日我们公布了获奖名单（），对这份名单的前6名的成绩存有疑问，根据题目数量与他们的答题日期和完成时间，初步判断是作弊行为。当然，咱们也不能一棍子打死，给人家一个机会解释，另外我也想认识这几位大神，对我们小麦和我们公众号了解这么多，一定是非凡人。 后面那个排名第一自称李周的人联系我们。他开门见山就说我就是第一名，凭什么质疑他之类的话。我说，你报下你的手机号，我稍后会核实你与那个第一名是否是同一人。结果人家不理我，自顾自的在喷我。我看这态势不像是来解决问题的，我索性就拉黑了。真要感谢微信的拉黑功能，世界顿时清静了。 后面Google他们的手机号之后，发现网上有人举报他们是骗子，同时在防骗数据库查也能查到他们的电话（ http://new.fpsjk.cn/searchList_Detail.aspx?date=2017-04-05 ）（下图是曝光的骗子电话，希望能够帮助后来人），另外也可能是羊毛党。我不是反对薅羊毛，但请低调点不要被看出来。至此事情对我来说已告一段落。现在网络发达，也提醒大家注意网上防骗。我其实感到挺高兴，毕竟他们不是我们小麦人。我对我们这样一个群体是抱有预想的，或者说我们这样一个群体其实是有共同目标的。也因为有这样的共同目标和追求，我们才能聚集在一起。在我们群体里，不会容忍造假行为。这就是为什么我会感到高兴的主要原因。 说完了骗子，我们再说说这次真正的前十名，名单见下图。恭喜这些小伙伴，今天有时间的时候留意下话费是否到账。 终于，让我们进入正题，这一周有几篇文献还是不错的，思路和方法上值得学习和借鉴。 1 Integrated physical map of bread wheat chromosome arm 7DS to facilitate gene cloning and comparative studies Bread wheat ( Triticum aestivum L.) is a staple food for a significant part of the world’s population. The growing demand on its production can be satisfied by improving yield and resistance to biotic and abiotic stress. Knowledge of the genome sequence would aid in discovering genes and QTLs underlying these traits and provide a basis for genomics-assisted breeding. Physical maps and BAC clones associated with them have been valuable resources from which to generate a reference genome of bread wheat and to assist map-based gene cloning. As a part of a joint effort coordinated by the International Wheat Genome Sequencing Consortium, we have constructed a BAC-based physical map of bread wheat chromosome arm 7DS consisting of 895 contigs and covering 94% of its estimated length. By anchoring BAC contigs to one radiation hybrid map and three high resolution genetic maps, we assigned 73% of the assembly to a distinct genomic position. This map integration, interconnecting a total of 1,713 markers with ordered and sequenced BAC clones from a minimal tiling path, provides a tool to speed up gene cloning in wheat. The process of physical map assembly included the integration of the 7DS physical map with a whole-genome physical map of Aegilops tauschii and a 7DS Bionano genome map, which together enabled efficient scaffolding of physical-map contigs, even in the non-recombining region of the genetic centromere. Moreover, this approach facilitated a comparison of bread wheat and its ancestor at BAC-contig level and revealed a reconstructed region in the 7DS pericentromere. 2 Transcriptome reprogramming due to the introduction of a barley telosome into bread wheat affects more barley genes than wheat Despite a long history, the production of useful alien introgression lines in wheat remains difficult mainly due to linkage drag and incomplete genetic compensation. In addition, little is known about the molecular mechanisms underlying the impact of foreign chromatin on plant phenotype. Here, a comparison of the transcriptomes of barley, wheat and a wheat barley 7HL addition line allowed the transcriptional impact both on 7HL genes of a non-native genetic background, and on the wheat gene complement as a result of the presence of 7HL to be assessed. Some 42% (389/923) of the 7HL genes assayed were differentially transcribed, which was the case for only 3% (960/35,301) of the wheat gene complement. The absence of any transcript in the addition line of a suite of chromosome 7A genes implied the presence of a 36 Mbp deletion at the distal end of the 7AL arm; this deletion was found to be in common across the full set of Chinese Spring/Betzes barley addition lines. The remaining differentially transcribed wheat genes were distributed across the whole genome. The up-regulated barley genes were mostly located in the proximal part of the 7HL arm, while the down-regulated ones were concentrated in the distal part; as a result, genes encoding basal cellular functions tended to be transcribed, while those encoding specific functions were suppressed. An insight has been gained into gene transcription in an alien introgression line, thereby providing a basis for understanding the interactions between wheat and exotic genes in introgression materials. 3 Zinc and Iron Concentration as Affected by Nitrogen Fertilization and Their Localization in Wheat Grain Nearly half of the world cereal production comes from soils low or marginal in plant available zinc, leading to unsustainable and poor quality grain production. Therefore, the effects of nitrogen (N) rate and application time on zinc (Zn) and iron (Fe) concentration in wheat grain were investigated. Wheat ( Triticum aestivum var. Krabat) was grown in a growth chamber with 8 and 16 h of day and night periods, respectively. The N rates were 29, 43, and 57 mg N kg-1 soil, equivalent to 80, 120, and 160 kg N ha-1. Zinc and Fe were applied at 10 mg kg-1 growth media. In one of the N treatments, additional Zn and Fe through foliar spray (6 mg of Zn or Fe in 10 ml water/pot) was applied. Micro-analytical localization of Zn and Fe within grain was performed using scanning macro-X-ray fluorescence (MA-XRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The following data were obtained: grain and straw yield pot-1, 1000 grains weight, number of grains pot-1, whole grain protein content, concentration of Zn and Fe in the grains. Grain yield increased from 80 to 120 kg N ha-1 rates only and decreased at 160 kg N ha-1 g. Relatively higher protein content and Zn and Fe concentration in the grain were recorded with the split N application of 160 kg N ha-1. Soil and foliar supply of Zn and Fe (Zn + Fes+f), with a single application of 120 kg N ha-1N at sowing, increased the concentration of Zn by 46% and of Fe by 35%, as compared to their growth media application only. Line scans of freshly cut areas of sliced grains showed co-localization of Zn and Fe within germ, crease and aleurone. We thus conclude that split application of N at 160 kg ha-1 at sowing and stem elongation, in combination with soil and foliar application of Zn and Fe, can be a good agricultural practice to enhance protein content and the Zn and Fe concentration in grain. 5 Genetic Dissection of End-Use Quality Traits in Adapted Soft White Winter Wheat Soft white wheat is used in domestic and foreign markets for various end products requiring specific quality profiles. Phenotyping for end-use quality traits can be costly, time-consuming and destructive in nature, so it is advantageous to use molecular markers to select experimental lines with superior traits. An association mapping panel of 469 soft white winter wheat cultivars and advanced generation breeding lines was developed from regional breeding programs in the U.S. Pacific Northwest. This panel was genotyped on a wheat-specific 90 K iSelect single nucleotide polymorphism (SNP) chip. A total of 15,229 high quality SNPs were selected and combined with best linear unbiased predictions (BLUPs) from historical phenotypic data of the genotypes in the panel. Genome-wide association mapping was conducted using the Fixed and random model Circulating Probability Unification (FarmCPU). A total of 105 significant marker-trait associations were detected across 19 chromosomes. Potentially new loci for total flour yield, lactic acid solvent retention capacity, flour sodium dodecyl sulfate sedimentation and flour swelling volume were also detected. Better understanding of the genetic factors impacting end-use quality enable breeders to more effectively discard poor quality germplasm and increase frequencies of favorable end-use quality alleles in their breeding populations. 6 Expression of TpNRAMP5, a metal transporter from Polish wheat ( Triticum polonicum L.), enhances the accumulation of Cd, Co and Mn in transgenic Arabidopsis plants Numerous natural resistance-associated macrophage proteins (NRAMPs) have been functionally identified in various plant species, including Arabidopsis , rice, soybean and tobacco, but no information is available on NRAMP genes in wheat. In this study, we isolated a TpNRAMP5 from dwarf Polish wheat (DPW, Triticum polonicum L.), a species with high tolerance to Cd and Zn. Expression pattern analysis revealed that TpNRAMP5 is mainly expressed in roots and basal stems of DPW. TpNRAMP5 was localized at the plasma membrane of Arabidopsis leaf protoplast. Expression of TpNRAMP5 in yeast significantly increased yeast sensitivity to Cd and Co, but not Zn, and enhanced Cd and Co concentrations. Expression of TpNRAMP5 in Arabidopsis significantly increased Cd, Co and Mn concentrations in roots, shoots and whole plants, but had no effect on Fe and Zn concentrations. These results indicate that TpNRAMP5 is a metal transporter enhancing the accumulation of Cd, Co and Mn, but not Zn and Fe. Genetic manipulation of TpNRAMP5 can be applied in the future to limit the transfer of Cd from soil to wheat grains, thereby protecting human health. 7 Molecular profiling of a y-type high molecular weight glutenin subunit at Glu-D1 locus from a North Korean landrace wheat ( Triticum aestivum L.) The objective of this study is to demonstrate characteristics of a y-type high molecular weight glutenin subunit (D1y HMW-GS) at Glu-D1 found in IT212991, a North Korean landrace wheat compared to Dy12 and Dy12.K as a novel HMW-GS in JB20, a Korean wheat line onto molecular analyses as PCR, cloning, DNA sequencing, and RP-HPLC and proteomic analyses as sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE), two-dimensional electrophoresis (2-DE), Fourier-transform mass spectrometry (LTQ-FT-MS). The D1y of IT212991 was identified to have faster electrophoretic mobility than that of Dy12 by SDS–PAGE. HMW-GS components of IT212991 were identified to be different from Chinese Spring (CS) and JB20, a Korean wheat line by RP-HPLC. The result of mass spectrometric analysis, the D1y of IT212991 (68510.8 Da) was similar to that of Dy12.K of JB20 (68514.4 Da), and lower than Dy12 of CS (69151.2 Da). The result of LTQ-FT-MS based on 2-DE, the D1y of IT212991 was identified to be similar with Dy12 corresponding to the protein function as ‘Glutenin, high molecular weight subunit 12’. The D1y encoding the D1y of IT212991 was identified to consist of 652 amino acid sequences corresponding to 1962 bp according to DNA sequencing. The gene was identified to have a insertion and deletion (InDel) corresponding to 18 bp sequences ‘AACAGGACAAGGGCAACA’ compared to ordinary Dy12 gene. It was demonstrated that the D1y of IT212991 is the same as Dy12.K. 8 Responses of seminal wheat seedling roots to soil water deficits The aims of this paper are to develop our understanding of the ways by which soil water deficits influence early wheat root growth responses, particularly how seminal roots respond to soil drying and the extent to which information on differences in soil water content are conveyed to the shoot and their impact on shoot behaviour. To achieve this, wheat seedlings have been grown, individually for around 25 days after germination in segmented soil columns within vertical plastic compartments. Roots were exposed to different soil volumetric moisture contents (SVMC) within the two compartments. Experiments where the soil in the lower compartment was allowed to dry to different extents, while the upper was maintained close to field capacity, showed that wheat seedlings allocated proportionally more root dry matter to the lower drier soil compartment. The total production of root, irrespective of the upper or lower SVMC, was similar and there were no detected effects on leaf growth rate or gas exchange. The response of seminal roots to proportionally increase their allocation of dry matter, to the drier soil was unexpected with such plasticity of roots system development traditionally linked to heterogeneous nutrient distribution than accessing soil water. In experiments where the upper soil compartment was allowed to dry, root growth slowed and leaf growth and gas exchange declined. Subsequent experiments used root growth rates to determine when seminal root tips first came into contact with drying soil, with the intentions of determining how the observed root growth rates were maintained as an explanation for the observed changes in root allocation. Measurements of seminal root ABA and ethylene from roots within the drying soil are interpreted with respect to what is known about the physiological control of root growth in drying soil. 9 A wheat gene TaSAP17-D encoding an AN1/AN1 zinc finger protein improves salt stress tolerance in transgenic Arabidopsis The stress-associated protein (SAP) multigene family is conserved in both animals and plants. Its function in some animals and plants are known, but it is yet to be deciphered in wheat ( Triticum aestivum L.). We identified the wheat gene TaSAP17-D, a member of the SAP gene family with an AN1/AN1 conserved domain. Subcellular localization indicated that TaSAP17-D localized to the nucleus, cytoplasm, and cell membrane. Expression pattern analyses revealed that TaSAP17-D was highly expressed in seedlings and was involved in NaCl response, polyethylene glycol (PEG), cold, and exogenous abscisic acid (ABA). Constitutive expression of TaSAP17-D in transgenic Arabidopsis resulted in enhanced tolerance to salt stress, confirmed by improved multiple physiological indices and significantly upregulated marker genes related to salt stress response. Our results suggest that TaSAP17-D is a candidate gene that can be used to protect crop plants from salt stress. 10 Light interception and radiation use efficiency response to tridimensional uniform sowing in winter wheat improving radiation use efficiency (RUE) of the canopy is necessary to increase wheat ( Triticum aestivum ) production. Tridimensional uniform sowing (U) technology has previously been used to construct a uniformly distributed population structure that increases RUE. In this study, we used tridimensional uniform sowing to create a wheat canopy within which light was spread evenly to increase RUE. This study was done during 2014–2016 in the Shunyi District, Beijing, China. The soil type was sandy loam. Wheat was grown in two sowing patterns: (1) tridimensional uniform sowing (U); (2) conventional drilling (D). Four planting densities were used: 1.8, 2.7, 3.6, and 4.5 million plants ha−1. Several indices were measured to compare the wheat canopies: photosynthetic active radiation intercepted by the canopy (IPAR), leaf area index (LAI), leaf mass per unit area (LMA), canopy extinction coefficient (K), and RUE. In two sowing patterns, the K values decreased with increasing planting density, but the K values of U were lower than that of D. LMA and IPAR were higher for U than for D, whereas LAI was nearly the same for both sowing patterns. IPAR and LAI increased with increasing density under the same sowing pattern. However, the difference in IPAR and LAI between the 3.6 and 4.5 million plants ha−1 treatments was not significant for both sowing patterns. Therefore, LAI within the same planting density was not affected by sowing pattern. RUE was the largest for the U mode with a planting density of 3.6 million plants ha−1 treatment. For the D sowing pattern, the lowest planting density (1.8 million plants ha−1) resulted in the highest yield. Light radiation interception was minimal for the D mode with a planting density of 1.8 million plants ha−1 treatment, but the highest RUE and highest yield were observed under this condition. For the U sowing pattern, IPAR increased with increasing planting density, but yield and RUE were the highest with a planting density of 3.6 million plants ha−1. These results indicated that the optimal planting density for improving the canopy light environment differed between the sowing patterns. The effect of sowing pattern×planting density interaction on grain yield, yield components, RUE, IPAR, and LMA was significant ( P 0.05). Correlation analysis indicated that there is a positive significant correlation between grain yield and RUE ( r =0.880, P 0.01), LMA ( r =0.613, P 0.05), and spike number ( r =0.624, P 0.05). These results demonstrated that the tridimensional uniform sowing technique, particularly at a planting density of 3.6 million plants ha−1, can effectively increase light interception and utilization and unit leaf area. This leads to the production of more photosynthetic products that in turn lead to significantly increased spike number ( P 0.05), kernel number, grain weight, and an overall increase in yield. 11 Evaluating the Profitability of Foliar Fungicide Programs in Mid-Atlantic Soft-Red Winter Wheat Production In mid-Atlantic soft-red winter wheat (SRWW) production, the standard timing for a fungicide application is between flag leaf emergence (Feekes growth stage 8) and heading (FGS 10.5). However, two-pass and anthesis (FGS 10.5.1) applications are becoming common, yet these programs have not been thoroughly evaluated for disease control, yield, and profitability. Experiments were conducted in the mid-Atlantic in 2015 and 2016 to evaluate fungicide programs with applications at FGS 8, FGS 10.5.1, and two-pass programs with an early application at green-up (FGS 5) followed by (FB) applications at either FGS 8 or FGS 10.5.1. Fungicide programs including an application at FGS 10.5.1 resulted in the highest probability of no disease on the flag leaf (0.29-0.40). The estimated mean yield increases (D ̅) relative to the non-treated check ranged from 253.65 to 634.16 kg ha-1. Using a grain price of 5 bu-1), probabilities were similar between applications at FGS 8 (0.49 to 0.56) and FGS 10.5.1 (0.53). The probability of profitability ranged from 0.48 to 0.57 for FGS 5 FB FGS 8 applications and 0.52 to 0.59 for FGS 5 FB FGS 10.5.1 applications, indicating limited benefit to two-pass programs. 12 Epigenetic perspectives on the evolution and domestication of polyploid plant and crops Polyploidy or whole genome duplication (WGD) is a prominent feature for genome evolution of some animals and all flowering plants, including many important crops such as wheat, cotton, and canola. In autopolyploids, genome duplication often perturbs dosage regulation on biological networks. In allopolyploids, interspecific hybridization could induce genetic and epigenetic changes, the effects of which could be amplified by genome doubling (ploidy changes). Albeit the importance of genetic changes, some epigenetic changes can be stabilized and transmitted as epialleles into the progeny, which are subject to natural selection, adaptation, and domestication. Here we review recent advances for general and specific roles of epigenetic changes in the evolution of flowering plants and domestication of agricultural crops. 13 Wheat stripe rust resistance gene Yr24/Yr26 : A retrospective review The objective of this review is to describe events in China and elsewhere that are related to the discovery, genetic identification, use, and ultimate break-down of a single wheat gene for resistance to stripe rust, namely Yr24/Yr26 . In our retrospective analysis there was an early assumption of at least three genes at or near the locus, which caused an erroneous presumption of genetic diversity for resistance. It is an example of another boom and bust cycle in plant breeding with races virulent to Yr26 (V26 races) now being the majority race group in the Chinese Pst population. We have attempted to present our story in a historical and personal context demonstrating research inputs from different national and international groups, as well as some significant contemporary side issues. It covers the period from the late 1980s to 2017, during which significant rapid advances in the molecular biology of host: pathogen genetics occurred. We attempt to describe both successes and drawbacks in our work. 14 Mapping a leaf senescence gene els1 by BSR-seq in common wheat Leaf senescence is normally the last stage of plant development. Early senescence of functional leaves significantly reduces the photosynthetic time and efficiency, seriously affecting grain yield and quality in wheat. Discovering genes responsible for early leaf senescence ( els ) are necessary for developing novel germplasms and cultivars with delayed leaf-senescence through molecular manipulation and marker assisted selection. In this study, we identified an early leaf senescence line M114 in a derivative of a wheat breeding population. Genetic analysis indicated that early leaf senescence in M114 is controlled by a single recessive gene, provisionally designated els1 . By applying bulked segregant analysis and RNA-Seq (BSR-Seq), seven polymorphic markers linked to els1 were developed and the gene was located on chromosome arm 2BS in a 1.5 cM genetic interval between markers WGGB303 and WGGB305 . A co-segregating marker, WGGB302 , provide a starting point for fine mapping and map-based cloning of els1 . 15 Effects of sulfur fertilization and short-term high temperature on wheat grain production and wheat flour proteins The content of wheat flour proteins affects the quality of wheat flour. Sulfur nutrition in wheat can change the protein content of the flour. The inconsistency and instability of wheat grain quality during grain filling under high temperature stress (HTS) are a major challenge to the production of high-quality wheat. The effects of sulfur fertilization and HTS on wheat flour protein and its components are unknown. In this study, treatments varying two factors: sulfur fertilization and exposure to short-term HTS, at 20 days post-anthesis, were applied to two wheat cultivars with differing gluten types. Plants of a strong-gluten wheat (Gaoyou 2018) and a medium-gluten wheat (Zhongmai 8) were grown in pots in Beijing in 2015–2017. HTS significantly increased the contents of total protein, albumin, gliadin, glutenin, Cys, and Met in wheat kernels, but reduced grain yield, grain weight, protein yield, globulin content, and total starch accumulation. The HTS-induced increase in total protein amount was closely associated with nitrate reductase (NR) and glutamine synthetase (GS) activities in flag leaves. Sulfur fertilization increased grain and protein yields; grain weight; total protein, albumin, gliadin, glutenin, and globulin contents; protein yield; total starch; Cys, Met; and NR and GS activities. HTS and sulfur fertilization had larger effects on the strong- than on the medium-gluten cultivar. Sulfur fertilization also alleviated the negative effects of HTS on grain yield, protein yield, and starch content. Thus, growing wheat with additional soil sulfur can improve the quality of the flour. 16 Low pH stress responsive transcriptome of seedling roots in wheat ( Triticum aestivum L.) Soil acidification is one of major problems limiting crop growth and especially becoming increasingly serious in China owing to excessive use of nitrogen fertilizer. Only the STOP1 of Arabidopsis was identified clearly sensitive to proton rhizotoxicity and the molecular mechanism for proton toxicity tolerance of plants is still poorly understood. The main objective of this study was to investigate the transcriptomic change in plants under the low pH stress. The low pH as a single factor was employed to induce the response of the wheat seedling roots. Wheat cDNA microarray was used to identify differentially expressed genes (DEGs). A total of 1057 DEGs were identified, of which 761 genes were up-regulated and 296 were down-regulated. The greater percentage of up-regulated genes involved in developmental processes, immune system processes, multi-organism processes, positive regulation of biological processes and metabolic processes of the biological processes. The more proportion of down-regulation genes belong to the molecular function category including transporter activity, antioxidant activity and molecular transducer activity and to the extracellular region of the cellular components category. Moreover, most genes among 41 genes involved in ion binding, 17 WAKY transcription factor genes and 17 genes related to transport activity were up-regulated. KEGG analysis showed that the jasmonate signal transduction and flavonoid biosynthesis might play important roles in response to the low pH stress in wheat seedling roots. Based on the data, it is can be deduced that WRKY transcription factors might play a critical role in the transcriptional regulation, and the alkalifying of the rhizosphere might be the earliest response process to low pH stress in wheat seedling roots. These results provide a basis to reveal the molecular mechanism of proton toxicity tolerance in plants. 17 High Relative Parasitic Fitness of G22 Derivatives is Associated with the Epidemic Potential of Wheat Stripe Rust in China In total, 13 commercial wheat cultivars around China and four races of Puccinia striiformis f. sp. tritici (namely, CYR32, CYR33, G22-9, and G22-14) were employed for a test of relative parasitic fitness (RPF) using the drop method. The RPF values were measured, including the urediniospore germination rate, the latent period, the uredinial length, the uredinial density, the infection area, the sporulation intensity, the lesion expansion speed, and the sporulation period. The results indicated that the parameters of relative parasitic fitness of the four P. striiformis f. sp. tritici races on the 13 wheat cultivars were significantly different ( P = 0.00) in sporulation intensity, lesion expansion speed, uredinial length, sporulation period, uredinial density, and latent period. The urediniospore germination rates of the four P. striiformis f. sp. tritici races for the test were significantly different ( P = 0.00), whereas no correlation with the different cultivars was observed ( P = 1.00). The infection areas of the tested races on the different cultivars were significantly different ( P = 0.00) but there were no obvious manifestations among the various races ( P = 0.20). Principal component analysis (PCA) showed that the sporulation intensity represented sporulation capacity and scalability, the latent period indicated infection ability, and the urediniospore germination rate represented urediniospore vigor, all of which fully contributed to the RPF in the interaction of the four races and 13 wheat cultivars, which was calculated by the following formula: RPF = (sporulation intensity × urediniospore germination rate)/latent period. The sporulation and infection of G22-9 on the 13 large-scale cultivated cultivars were the highest, and the RPF of G22-9 was higher than that of the predominant races, CYR32 and CYR33. This result suggested that G22-9 could become a new predominant race and potentially cause epidemics of wheat stripe rust in China. To prevent potential epidemics, susceptible wheat cultivars should be withdrawn from production and breeding programs should reduce the use of Yr10 and Yr26 and use other more effective resistance genes in combination with nonrace-specific resistance for developing wheat cultivars with durable resistance to stripe rust. 18 Genome-Wide Identification and Characterization of Long Non-Coding RNA in Wheat Roots in Response to Ca2+Channel Blocker It remains unclear whether plant lncRNAs are responsive to Ca2+-channel blocking. When using the Ca2+-channel blocker, LaCl3, to treat germinated wheat seeds for 24 h, we found that both root length and mitosis were inhibited in the LaCl3-treated groups. The effect of the Ca2+-channel blocker was verified in three ways: a cyt decrease detected using Fluo-3/AM staining, a decrease in the Ca content measured using inductively coupled plasma mass spectrometry, and an inhibition of Ca2+ influx detected using Non-invasive Micro-test Technology. Genome-wide high throughput RNA-seq and bioinformatical methods were used to identify lncRNAs, and found 177 differentially expressed lncRNAs that might be in responsive to Ca2+-channel blocking. Among these, 108 were up-regulated and 69 were down-regulated. The validity of identified lncRNAs data from RNA-seq was verified using qPCR. GO and KEGG analysis indicated that a number of lncRNAs might be involved in diverse biological processes upon Ca2+-channel blocking. Further GO analysis showed that 23 lncRNAs might play roles as transcription factor (TF); Moreover, eight lncRNAs might participate in cell cycle regulation, and their relative expressions were detected using qPCR. This study also provides diverse data on wheat lncRNAs that can deepen our understanding of the function and regulatory mechanism of Ca2+-channel blocking in plants. 19 Simultaneous improvement of grain yield and protein content in durum wheat by different phenotypic indices and genomic selection Grain yield and protein content are of major importance in durum wheat breeding, but their negative correlation has hampered their simultaneous improvement. To account for this in wheat breeding, the grain protein deviation (GPD) and the protein yield were proposed as targets for selection. The aim of this work was to investigate the potential of different indices to simultaneously improve grain yield and protein content in durum wheat and to evaluate their genetic architecture towards genomics-assisted breeding. To this end, we investigated two different durum wheat panels comprising 159 and 189 genotypes, which were tested in multiple field locations across Europe and genotyped by a genotyping-by-sequencing approach. The phenotypic analyses revealed significant genetic variances for all traits and heritabilities of the phenotypic indices that were in a similar range as those of grain yield and protein content. The GPD showed a high and positive correlation with protein content, whereas protein yield was highly and positively correlated with grain yield. Thus, selecting for a high GPD would mainly increase the protein content whereas a selection based on protein yield would mainly improve grain yield, but a combination of both indices allows to balance this selection. The genome-wide association mapping revealed a complex genetic architecture for all traits with most QTL having small effects and being detected only in one germplasm set, thus limiting the potential of marker-assisted selection for trait improvement. By contrast, genome-wide prediction appeared promising but its performance strongly depends on the relatedness between training and prediction sets. 20 RNAi-Mediated Downregulation of Inositol Pentakisphosphate Kinase ( IPK1 ) in Wheat Grains Decreases Phytic Acid Levels and Increases Fe and Zn Accumulation Enhancement of micronutrient bioavailability is crucial to address the malnutrition in the developing countries. Various approaches employed to address the micronutrient bioavailability are showing promising signs, especially in cereal crops. Phytic acid (PA) is considered as a major antinutrient due to its ability to chelate important micronutrients and thereby restricting their bioavailability. Therefore, manipulating PA biosynthesis pathway has largely been explored to overcome the pleiotropic effect in different crop species. Recently, we reported that functional wheat inositol penta kis phosphate kinase ( TaIPK1 ) is involved in PA biosynthesis, however, the functional roles of the IPK1 gene in wheat remains elusive. In this study, RNAi-mediated gene silencing was performed for IPK1 transcripts in hexaploid wheat. Four non-segregating RNAi lines of wheat were selected for detailed study (S3-D-6-1; S6-K-3-3; S6-K-6-10 and S16-D-9-5). Homozygous transgenic RNAi lines at T4 seeds with a decreased transcript of TaIPK1 showed 28–56% reduction of the PA. Silencing of IPK1 also resulted in increased free phosphate in mature grains. Although, no phenotypic changes in the spike was observed but, lowering of grain PA resulted in the reduced number of seeds per spikelet. The lowering of grain PA was also accompanied by a significant increase in iron (Fe) and zinc (Zn) content, thereby enhancing their molar ratios (Zn:PA and Fe:PA). Overall, this work suggests that IPK1 is a promising candidate for employing genome editing tools to address the mineral accumulation in wheat grains. 21 Evaluation of end use quality and root traits in wheat cultivars associated with 1RS.1BL translocation 1RS.1BL translocation in wheat, exploited for its multiple disease resistance ( Lr26, Yr9, Sr31 and Pm8 ), has maintained significance due to its agronomical advantages. However, this translocation exhibits serious defects in dough quality due to the presence of Sec - 1 loci on 1RS arm. In the present investigation micro SDS sedimentation test (MST), high molecular weight glutenin subunits (HMWGS) and bread making analysis of 26 genotypes were studied along with their root phenotyping in the field and under hydroponic culture system. The MST values showed that genotypes having Sec -1 loci had low MST values but in the presence of Glu-D1 (5 + 10) with Glu-B1 (7 + 9) and (7 + 8) they had high MST values, thus overcoming the negative effects of secalin on dough quality. The loaf volume showed positive correlation with MST values of the genotypes. The translocation of 1RS arm led to higher root biomass and longer root length than Pavon 76 without 1RS. Better root traits in recombinant 1RS 44:38 and 1B + 38 than Pavon 1RS.1BL suggested the role of negative epistatic effects between different QTL regions in 1RS arm. The results suggest that it should be possible to harness the useful alleles associated with good dough quality, better root traits, high yield and stress tolerance with or without secalin. 22 Three endoplasmic reticulum-associated fatty acyl-coenzyme a reductases were involved in the production of primary alcohols in hexaploid wheat ( Triticum aestivum L.) We reported the cloning and characterization of three TaFARs, namely TaFAR6 , TaFAR7 and TaFAR8 , encoding fatty acyl-coenzyme A reductases (FAR) in wheat leaf cuticle. Expression analysis revealed that TaFAR6 , TaFAR7 and TaFAR8 were expressed at the higher levels in the seedling leaf blades, and were expressed moderately or weakly in stamen, glumes, peduncle, flag leaf blade, sheath, spike, and pistil. The heterologous expression of three TaFARs in yeast ( Saccharomyces cerevisiae ) led to the production of C24:0 and C26:0 primary alcohols. Transgenic expression of the three TaFARs in tomato ( Solanum lycopersicum ) and rice ( Oryza sativa ) led to increased accumulation of C24:0–C30:0 primary alcohols. Transient expression of GFP protein-tagged TaFARs revealed that the three TaFAR proteins were localized to the endoplasmic reticulum (ER), the site of wax biosynthesis. The three TaFAR genes were transcriptionally induced by drought, cold, heat, powdery mildew ( Blumeria graminis ) infection, abscisic acid (ABA) and methyl jasmonate (MeJa) treatments. 23 Analysis of MAPK and MAPKK gene families in wheat and related Triticeae species The work presented here focuses on two subfamilies of Triticeae MAPKs, the MAP kinases (MPKs), and the MAPK kinases (MKKs) whose members phosphorylate the MPKs. In silico analysis of multiple Triticeae sequence databases led to the identification of 152 MAPKs belonging to these two sub-families. Some previously identified MAPKs were renamed to reflect the literature consensus on MAPK nomenclature. Two novel MPKs, MPK24 and MPK25, have been identified, including the first example of a plant MPK carrying the TGY activation loop sequence common to mammalian p38 MPKs. An EF-hand calcium-binding domain was found in members of the Triticeae MPK17 clade, a feature that appears to be specific to Triticeae species. New insights into the novel MEY activation loop identified in MPK11s are offered. When the exon-intron patterns for some MPKs and MKKs of wheat, barley and ancestors of wheat were assembled based on transcript data in GenBank, they showed deviations from the same sequence predicted in Ensembl. The functional relevance of MAPKs as derived from patterns of gene expression, MPK activation and MKK-MPK interaction is discussed. 24 Transcriptome analysis of wheat seedling and spike tissues in the hybrid Jingmai 8 uncovered genes involved in heterosis Heterosis, known as one of the most successful strategies for increasing crop yield, has been widely exploited in plant breeding systems. Despite its great importance, the molecular mechanism underlying heterosis remains elusive. In the present study, RNA sequencing (RNA-seq) was performed on the seedling and spike tissues of the wheat ( Triticum aestivum ) hybrid Jingmai 8 (JM8) and its homozygous parents to unravel the underlying mechanisms of wheat heterosis. In total, 1686 and 2334 genes were identified as differentially expressed genes (DEGs) between the hybrid and the two inbred lines in seedling and spike tissues, respectively. Gene Ontology analysis revealed that DEGs from seedling tissues were significantly enriched in processes involved in photosynthesis and carbon fixation, and the majority of these DEGs expressed at a higher level in JM8 compared to both inbred lines. In addition, cell wall biogenesis and protein biosynthesis-related pathways were also significantly represented. These results confirmed that a combination of different pathways could contribute to heterosis. The DEGs between the hybrid and the two inbred progenitors from the spike tissues were significantly enriched in biological processes related to transcription, RNA biosynthesis and molecular function categories related to transcription factor activities. Furthermore, transcription factors such as NAC , ERF , and TIF-IIA were highly expressed in the hybrid JM8. These results may provide valuable insights into the molecular mechanisms underlying wheat heterosis. 25 A Comparison Between Genotyping-by-sequencing and Array-based Scoring of SNPs for Genomic Prediction Accuracy in Winter Wheat The utilization of DNA molecular markers in plant breeding to maximize selection response via marker-assisted selection (MAS) and genomic selection (GS) has revolutionized plant breeding. A key factor affecting GS applicability is the choice of molecular marker platform. Genotyping-by-sequencing scored SNPs (GBS-scored SNPs) provides a large number of markers, albeit with high rates of missing data. Array scored SNPs are of high quality, but the cost per sample is substantially higher. The objectives of this study were 1) compare GBS-scored SNPs, and array scored SNPs for genomic selection applications, and 2) compare estimates of genomic kinship and population structure calculated using the two marker platforms. SNPs were compared in a diversity panel consisting of 299 hard winter wheat ( Triticum aestivum L.) accessions that were part of a multi-year, multi-environments association mapping study. The panel was phenotyped in Ithaca, Nebraska for heading date, plant height, days to physiological maturity and grain yield in 2012 and 2013. The panel was genotyped using GBS-scored SNPs, and array scored SNPs. Results indicate that GBS-scored SNPs is comparable to or better than Array-scored SNPs for genomic prediction application. Both platforms identified the same genetic patterns in the panel where 90% of the lines were classified to common genetic groups. Overall, we concluded that GBS-scored SNPs have the potential to be the marker platform of choice for genetic diversity and genomic selection in winter wheat. 26 Isochorismate-based salicylic acid biosynthesis confers basal resistance to Fusarium graminearum in barley Salicylic acid (SA) plays an important role in signal transduction and disease resistance. In Arabidopsis , SA can be made by either of two biosynthetic branches, one involving isochorismate synthase (ICS) and the other involving phenylalanine ammonia lyase (PAL). However, the biosynthetic pathway and the importance of SA remains largely unknown in Triticeae. Here, we cloned one ICS and seven PAL genes from barley, and studied their functions by overexpressing and suppressing them in that plant. Suppression of the ICS gene significantly delayed plant growth, while PAL genes, both overexpressed and suppressed, had no significant effect on plant growth. Similarly, suppression of the ICS compromised plant resistance to Fusarium graminearum , while similar suppression of PAL genes had no significant effect. We then focused on transgenic plants with ICS . In a leaf-based test with F. graminearum , transgenic plants with an upregulated ICS were comparable to the wild-type control plants. By contrast, transgenic plants with a suppressed ICS lost the ability to accumulate SA during pathogen infection and were also more susceptible to Fusarium than the wild-type controls. This suggests that ICS plays a unique role in SA biosynthesis in barley, which in turn confers a basal resistance to F. graminearum by modulating the accumulation of H2O2, O2-, and reactive-oxygen associated enzymatic activities. Although SA mediates systemic acquired resistance (SAR) in dicots, there was no comparable SAR response to F. graminearum in barley. This study expands our knowledge about SA biosynthesis in barley and proves that SA confers basal resistance for fungal pathogens. This article is protected by copyright. All rights reserved. 27 Barley yellow dwarf virus Infection Leads to Higher Chemical Defense Signals and Lower Electrophysiological Reactions in Susceptible Compared to Tolerant Barley Genotypes Barley yellow dwarf virus (BYDV) is a phloem limited virus that is persistently transmitted by aphids. Due to huge yield losses in agriculture, the virus is of high economic relevance. Since the control of the virus itself is not possible, tolerant barley genotypes are considered as the most effective approach to avoid yield losses. Although several genes and quantitative trait loci are known and used in barley breeding for virus tolerance, little is known about molecular and physiological backgrounds of this trait. Therefore, we compared the anatomy and early defense responses of a virus susceptible to those of a virus-tolerant cultivar. One of the very early defense responses is the transmission of electrophysiological reactions. Electrophysiological reactions to BYDV infection might differ between susceptible and tolerant cultivars, since BYDV causes disintegration of sieve elements in susceptible cultivars. The structure of vascular bundles, xylem vessels and sieve elements was examined using microscopy. All three were significantly decreased in size in infected susceptible plants where the virus causes disintegration of sieve elements. This could be associated with an uncontrolled ion exchange between the sieve-element lumen and apoplast. Further, a reduced electrophysiological isolation would negatively affect the propagation of electrophysiological reactions. To test the influence of BYDV infection on electrophysiological reactions, electropotential waves (EPWs) induced by leaf-tip burning were recorded using aphids as bioelectrodes. EPWs in infected susceptible plants disappeared already after 10 cm in contrast to those in healthy susceptible or infected tolerant or healthy tolerant plants. Another early plant defense reaction is an increase in reactive oxygen species (ROS). Using a fluorescent dye, we found a significant increase in ROS content in infected susceptible plants but not in infected tolerant plants. Similar results were found for the phytohormones abscisic acid and three jasmonates. Salicylic acid levels were generally higher after BYDV infection compared to uninfected plants. Heat stimulation caused an increase in jasmonates. By shedding light on the plant defense mechanisms against BYDV, this study, provides further knowledge for breeding virus tolerant plants. 28 Polymorphism of floral type gene Cly1 and its association with thermal stress in barley Cleistogamy refers to a type of sexual breeding system with closed flowers. Cleistogamous flowers shed their pollen before flower opening, which leads to autogamy. Two SNPs in the open reading frame region of the Cly1 gene are associated with floral type. In the present study, we investigated the floral type of 436 barley accessions. Molecular markers were developed to genotype these barley accessions based on the two SNPs in the Cly1 gene region. The molecular markers explained floral type in 90% of the accessions. The Cly1 gene was sequenced in accessions with inconsistent genotype and phenotype. Thirteen SNPs were detected with ten new SNPs in the gene region. We further investigated whether floral type was associated with temperature stress tolerance in four field trials. One site experienced frost stress with a minimum temperature of -3.4°C during flowering. Grain fertility rates as low as 85% were observed at this site but ranged from 92–96% at the other three sites. The relationship between grain fertility rate and floral type under temperature stress was inconclusive. Some lines with higher grain fertility rates were identified under frost stress, and would be useful for frost stress studies in barley.
小麦一周文献推荐（12.17） 1、QTL analysis of falling number and seed longevity in wheat (Triticum aestivum L.) Pre-harvest sprouting (PHS) and seed longevity (SL) are complex biological processes of major importance for agricultural production. In the present study, a recombinant inbred line (RIL) population derived from a cross between the German winter wheat (Triticum aestivum L.) cultivars History and Rubens was used to identify genetic factors controlling these two physiological seed traits. A falling number (FN) test was employed to evaluate PHS, while SL was measured using a germination test (and the speed of germination) after controlled deterioration. FN of the population was assessed in four environments; SL traits were measured in one environment. Four major quantitative trait loci (QTL) for FN were detected on chromosomes 4D, 5A, 5D, and 7B, whereas for SL traits, a major QTL was found on chromosome 1A. The FN QTL on chromosome 4D that coincided with the position of the dwarfing gene Rht-D1b only had effects in environments that were free of PHS. The remaining three QTL for FN were mostly pronounced under conditions conducive to PHS. The QTL on the long arm of chromosome 7B corresponded to the major gene locus controlling late maturity α-amylase (LMA) in wheat. The severity of the LMA phenotype became truly apparent under sprouting conditions. The position on the long arm of chromosome 1A of the QTL for SL points to a new QTL for this important regenerative seed trait. 2、RNA-seq facilitates development of chromosome-specific markers and transfer of rye chromatin to wheat Transcriptome shotgun sequencing (RNA-seq) provides an abundant resource for developing molecular markers specifically related to functional genes. In this study, transcriptomes of Chinese rye cultivar Jingzhouheimai (JZHM) challenged with powdery mildew pathogen Bgt ( Blumeria graminis f. sp. tritici ) were obtained and used to develop expressed sequence tag (EST)-based simple sequence repeat (SSR) and sequence-tagged site (STS) markers. A total of 866 primer sets for EST-SSRs and STSs were designed, from which we developed 401 rye-specific markers. The highest level of polymorphism was observed in EST-SSRs (56.73%) followed by STS2 (49.07%) designed via rye-specific contigs and STS1 (35.90%) primers designed from upregulated contigs. Genotyping with newly developed markers along with cytogenetic techniques allowed us to identify nine wheat alien chromosome lines from the cross of Zhoumai 18/Jinghui 1 (Jinghui 1 is an amphiploid of wheat landrace Huixianhong and JZHM) carrying rye chromosome 6R or 6R segments of different length, which permitted preliminary location of the powdery mildew resistance gene PmJZHM6RL and 12 specific markers to 6RL FL 0.51–1.0. 5R-specific markers and genomic in situ hybridization/fluorescence in situ hybridization detected MtA5RL and T5AS·5AL-5RL chromosomes among 41 F5 plants from the cross CS ph1bph1b /MA5R, and aberrations permitted the location of the hairy peduncle gene ( Hp ) and marker XLFZ3473 to the region 5RL FL 0.78–1.0 with another nine markers locating to 5RL 0.0–0.78. The chromosome-specific markers and chromosome aberrations developed in this study will facilitate the introgression of rye chromatin into wheat. 3、Genome-wide identification and characterization of NB-ARC resistant genes in wheat (Triticum aestivum L.) and their expression during leaf rust infection Wheat ( Triticum aestivum L.) is an important cereal crop; however, its production is affected severely by numerous diseases including rusts. An efficient, cost-effective and ecologically viable approach to control pathogens is through host resistance. In wheat, high numbers of resistance loci are present but only few have been identified and cloned. A comprehensive analysis of the NB-ARC-containing genes in complete wheat genome was accomplished in this study. Complete NB-ARC encoding genes were mined from the Ensembl Plants database to predict 604 NB-ARC containing sequences using the HMM approach. Genome-wide analysis of orthologous clusters in the NB-ARC-containing sequences of wheat and other members of the Poaceae family revealed maximum homology with Oryza sativa indica and Brachypodium distachyon . The identification of overlap between orthologous clusters enabled the elucidation of the function and evolution of resistance proteins. The distributions of the NB-ARC domain-containing sequences were found to be balanced among the three wheat sub-genomes. Wheat chromosome arms 4AL and 7BL had the most NB-ARC domain-containing contigs. The spatio-temporal expression profiling studies exemplified the positive role of these genes in resistant and susceptible wheat plants during incompatible and compatible interaction in response to the leaf rust pathogen Puccinia triticina . Two NB-ARC domain-containing sequences were modelled in silico, cloned and sequenced to analyze their fine structures. The data obtained in this study will augment isolation, characterization and application NB-ARC resistance genes in marker-assisted selection based breeding programs for improving rust resistance in wheat. 4、High-density SNP mapping reveals closely linked QTL for resistance to Stagonospora nodorum blotch (SNB) in flag leaf and glume of hexaploid wheat The genetic control of adult plant resistance to Stagonospora nodorum blotch (SNB) is complex consisting of genes with minor effects interacting in an additive manner. Earlier studies detected quantitative trait loci (QTL) for flag leaf resistance in successive years on chromosomes 1B, 2A, 2D, 5B using SSR- and DArT-based genetic maps of progeny from the crosses EGA Blanco/Millewa, 6HRWSN125/WAWHT2074 and P92201D5/P91193D1. Similarly, QTL for glume resistance detected in successive years and multiple environments were identified on chromosomes 2D and 4B from genetic maps of P92201D5/P91193D1 and 6HRWSN125/WAWHT2074, respectively. The SSR- and DArT-based genetic maps had an average distance of 6.5, 7.8 and 9.7 cM between marker loci for populations EGA/Millewa, P92201D5/P91193D1 and 6HRWSN125/WAWHT2074, respectively. This study used single nucleotide polymorphism (SNP) markers from the iSelect Infinium 90K genotyping array to fine map genomic regions harbouring QTL for flag leaf and glume SNB resistance reducing the average distance between markers to 2.9, 3.3 and 3.4 -3.4 cM for populations P92201D5/P91193D1, EGA/Millewa and 6HRWSN125/WAWHT2074, respectively. Increasing the marker density of the genetic maps with SNPs did not identify any new QTL for SNB resistance but discriminated previously identified co-located QTL into separate but closely linked QTL. 5、Review on resistance to wheat blast disease (Magnaporthe oryzae Triticum) from the breeder point-of-view: use of the experience on resistance to rice blast disease This review on the resistance to wheat blast disease focus on the latest knowledge useful for the breeders, but also takes into account the lacks in these knowledge. To tackle this disease, it is relevant to apply a breeding strategy which has previously proven its efficacy for obtaining rice varieties with a high level of partial and durable resistance to blast. But, incomplete information is available on wheat blast resistance. Therefore, firstly, it is necessary to adjust this breeding strategy considering the worst hypothesis corresponding to every lack of knowledge. Next, the possible invalidation of every hypothesis can allow simplifying the breeding schema and its implementation. For every lack of knowledge, the practical consequences of the corresponding worst hypothesis, the study of its validity and the consequences of its possible invalidation are explained. Scientific arguments, materials and methods details are provided with the latest available references. 6、Wheat genetic resources in the post-genomics era: promise and challenges 7、B genome specific polymorphism in the TdDRF1 gene is in relationship with grain yield A and B genome copies of DRF1 gene in durum wheat were isolated and sequenced using gene variability. B genome specific polymorphism resulted, in a RIL population, in relationship with grain yield mainly in drought condition. Drought tolerance is one of the main components of yield potential and stability, and its improvement is a major challenge to breeders. Transcription factors are considered among the best candidate genes for developing functional markers, since they are components of the signal transduction pathways that coordinate the expression of several downstream genes. Polymorphisms of the Triticum durum dehydration responsive factor 1 (TdDRF1) gene that belongs to DREB2 transcription factor family were identified and specifically assigned to the A or B genome. A panel of primers was derived to selectively isolate the corresponding gene copies. These molecular information were also used to develop a new molecular marker: an allele-specific PCR assay discriminating two genotypes (Mohawk and Cocorit) was developed and used for screening a durum wheat recombinant inbred line population (RIL-pop) derived from the above genotypes. Phenotypic data from the RIL-pop grown during two seasons, under different environmental conditions, adopting an α-lattice design with two repetitions, were collected, analyzed and correlated with molecular data from the PCR assay. A significant association between a specific polymorphism in the B genome copy of the TdDRF1 gene and the grain yield in drought conditions were observed. 8、QTL for stay-green traits in wheat in well-watered and water-limited environments “Stay-green” plants retain green leaf area longer after flowering than senescent types. This can prolong carbon assimilation during grain filling, increasing yield, particularly under terminal drought stress. A population of doubled haploid wheats ( Triticum aestivum L.) derived from a cross between stay-green SeriM82 and senescent Hartog was grown in eight environments with varying degrees of water limitation. The dynamics of normalised difference vegetative index (NDVI) was followed post-flowering to evaluate change in leaf greenness. Quantitative trait loci (QTL) were identified for components of stay-green including i) maximum NDVI (Nmax), ii) an indicator of the maximum rate of senescence (SR), iii) thermal time from flowering to commencement of senescence (OnS), iv) thermal time from flowering to mid-senescence (MidS), and v) the integral of NDVI from flowering to 1500 °Cd after flowering (SGint). Genetic regions associated with QTL for stay-green traits were identified (i) in both wet and dry environments on chromosomes 4A, 4B, 4D (constitutive stay-green); (ii) primarily in wetter environments on 2A and (iii) primarily in dryer environments on 5B. Other regions associated with QTL for stay-green were identified on 3B and 7B in a mixture of environment types. In some environments, stay-green QTL co-located with QTL for seminal root angle, seedling root number and/or for yield. Other stay-green QTL were co-located with yield but not seminal root angle and seedling root number. This suggests genetic regions associated with seminal root angle and seedling root number are not solely responsible for the high yielding, stay-green phenotype. Selection for stay-green traits will increase the rate of genetic progress for adaptation of wheat to both well-watered and water-limited environments. 9、An Advanced Backcross Population through Synthetic Octaploid Wheat as a “Bridge”: Development and QTL Detection for Seed Dormancy The seed dormancy characteristic is regarded as one of the most critical factors for pre-harvest sprouting (PHS) resistance. As a wild wheat relative species, Aegilops tauschii is a potential genetic resource for improving common wheat. In this study, an advanced backcross population (201 strains) containing only Ae. tauschii segments was developed by means of synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × Ae. tauschii T093). Subsequently, seed dormancy rate (Dor) in the advanced backcross population was evaluated on the day 3, 5 and 7, in which 2 major QTLs ( QDor-2D and QDor-3D ) were observed on chromosomes 2D and 3D with phenotypic variance explained values (PVEs) of 10.25 and 20.40%, respectively. Further investigation revealed significant correlation between QDor-3D and Tamyb10 gene, while no association was found between the former and TaVp1 gene, implying that QDor-3D site could be of closer position to Tamyb10 . The obtained quantitative trait locus sites (QTLs) in this work could be applied to develop wheat cultivars with PHS resistance. 10、miR430: the novel heat-responsive microRNA identified from miRNome analysis in wheat (Triticum aestivum L.) 11、Genetic and Molecular Characterization of Leaf Rust Resistance in Two Durum Wheat Landraces Leaf rust, caused by Puccinia triticina, is a constraint to durum wheat (Triticum turgidum subsp. durum) production, and landraces are reported to be an important source of resistance. Two Portuguese landraces (Aus26582 and Aus26579) showed resistance against durum-specific P. triticina races and were crossed with a susceptible landrace (Bansi) to develop recombinant inbred line (RIL) populations. Monogenic segregation for leaf rust resistance was observed among both RIL populations. The underlying locus, temporarily named LrAW2, was mapped to the short arm of chromosome 6B in the Aus26582/Bansi population and five DArTseq markers cosegregated with LrAW2. Simple sequence repeat markers sun683 and sun684, developed from the chromosome survey sequence (CSS) contig 6BS 2963854, identified through BlastN search of cosegregating DArTseq markers in the International Wheat Genome Sequencing Consortium database, cosegregated with LrAW2. Comparison of the CSS contig 6BS 2963854-based sequences amplified from parental genotypes led to the development of marker sunKASP 60, which also showed close linkage with LrAW2. Markers sun684 and sunKASP 60 showed close association with LrAW2 in both RIL populations. The amplification of LrAW2-specific products by linked markers in Aus26582, Aus26579, and Guayacan (Lr61) indicated that LrAW2 may be Lr61. The alternate amplicon or haplotype produced with LrAW2-linked markers in Australian durum cultivars demonstrated their effectiveness in marker-assisted selection. 12 Genetic Diversity, Population Structure and Ancestral Origin of Australian Wheat Since the introduction of wheat into Australia by the First Fleet settlers, germplasm from different geographical origins has been used to adapt wheat to the Australian climate through selection and breeding. In this paper, we used 482 cultivars, representing the breeding history of bread wheat in Australia since 1840, to characterize their diversity and population structure and to define the geographical ancestral background of Australian wheat germplasm. This was achieved by comparing them to a global wheat collection using in-silico chromosome painting based on SNP genotyping. The global collection involved 2,335 wheat accessions which was divided into 23 different geographical subpopulations. However, the whole set was reduced to 1,544 accessions to increase the differentiation and decrease the admixture among different global subpopulations to increase the power of the painting analysis. Our analysis revealed that the structure of Australian wheat germplasm and its geographic ancestors have changed significantly through time, especially after the Green Revolution. Before 1920, breeders used cultivars from around the world, but mainly Europe and Africa, to select potential cultivars that could tolerate Australian growing conditions. Between 1921 and 1970, a dependence on African wheat germplasm became more prevalent. Since 1970, a heavy reliance on International Maize and Wheat Improvement Center (CIMMYT) germplasm has persisted. Combining the results from linkage disequilibrium, population structure and in-silico painting revealed that the dependence on CIMMYT materials has varied among different Australian States, has shrunken the germplasm effective population size and produced larger linkage disequilibrium blocks. This study documents the evolutionary history of wheat breeding in Australia and provides an understanding for how the wheat genome has been adapted to local growing conditions. This information provides a guide for industry to assist with maintaining genetic diversity for long-term selection gains and to plan future breeding programs. 13 Natural variation in photoperiodic flowering pathway and identification of photoperiod-insensitive accessions in wild wheat, Aegilops tauschii The D-genome progenitor of hexaploid wheat, Aegilops tauschii Coss., has a wide natural species range in central Eurasia and possesses wide natural variation in heading and flowering time. Here, we report identification of two Ae. tauschii accessions insensitive to short day length. Similarly to a loss or reduced degree of vernalization requirement, the photoperiod-insensitive mutations were found only in the early flowering sublineage (TauL1b) of Ae. tauschii . Quantitative trait locus (QTL) analyses using two F2 mapping populations showed that a QTL for heading time on the long arm of chromosome 5D was related to the early heading phenotype of the photoperiod-insensitive accessions under short-day conditions. In the photoperiod-insensitive accession, expression patterns of two flowering-related genes were altered under short-day conditions compared with the patterns in photoperiod-sensitive accessions. This study indicates that analysis of natural variations in the Ae. tauschii population is useful to find novel genetic loci controlling agronomically important traits. 14 Genetic and physical mapping of a putative Leymus mollis-derived stripe rust resistance gene on wheat chromosome 4A | Plant Disease Wheat stripe rust is one of the most damaging diseases of wheat worldwide. The wheat–Leymus mollis introgression line M8664-3 exhibits all-stage resistance to Chinese stripe rust races. Genetic analysis of stripe rust resistance was performed by crossing M8664-3 with the susceptible line Mingxian169. Analysis of the disease resistance of F2 and F2:3 populations revealed that its resistance to Chinese stripe rust race 33(CYR33) is controlled by a single dominant gene, temporarily designated as YrM8664-3. Genetic and physical mapping showed that YrM8664-3 is located in bin 4AL13-0.59-0.66 close to 4AL12-0.43-0.59 on chromosome 4AL and is flanked by SNP markers AX111655681 and AX109496237 with genetic distances of 5.3 and 2.3 cM, respectively. Resistance spectrum and position analyses indicated that YrM8664-3 may be a novel gene. Molecular detection using the markers linked to YrM8664-3 with wheat varieties which commonly cultivated and wheat–L. mollis derived lines showed that YrM8664-3 is also present in other wheat–L. mollis introgression lines, but absent in commercial common wheat cultivars. YrM8664-3 is thus a potentially valuable source of stripe rust resistance for breeding. 15 A novel wheat cysteine-rich receptor-like kinase gene CRK41 is involved in the regulation of seed germination under osmotic stress in Arabidopsis thaliana The bread wheat gene TaCRK41 encodes a cysteine-rich receptor kinase. It is down-regulated by various abiotic stresses and by exposure to abscisic acid. A transient expression experiment in Arabidopsis thaliana protoplasts involving a fusion between the sequence encoding green fluorescence protein and the TaCRK41 allele from either the salinity tolerant bread wheat cultivar Shanrong No. 3 (SR3) or its salinity sensitive progenitor cultivar Jinan 177 (JN177) showed that the TaCRK41 product is deposited in the cytoplasm. Recombinant TaCRK41 originating from both SR3 and JN177 displayed no kinase activity in vitro . The constitutive expression of TaCRK41 in A. thaliana resulted in a marked reduction in the plants’ sensitivity to both exogenous abscisic acid and to salinity during germination. The level of ABA-induced transcription of ABI3 , ABI5 and the ABI5 -controlled genes EM1 and EM6 was significantly reduced in plants subjected to stress. The data support the idea that TaCRK41 is involved in the regulation of ABA-dependent germination under conditions of osmotic stress. 16 Characterization of QTLs for Root Traits of Wheat Grown under Different Nitrogen and Phosphorus Supply Levels Root is important in acquiring nutrients from soils. Developing marker-assisted selection for wheat root traits can help wheat breeders to select roots desirable for efficient acquisition of nutrients. A recombinant inbred line (RIL) population derived from wheat varieties Xiaoyan 54 and Jing 411 was used to detect QTLs for maximum root length and root dry weight (RDW) under control, low nitrogen and low phosphorus conditions in hydrophobic culture (HC). We totally detected 17 QTLs for the investigated root traits located at 13 loci on 11 chromosomes. These loci differentially expressed under different nutrient supplying levels. The RILs simultaneously harboring positive alleles or negative alleles of the most significant three QTLs for RDW, qRDW.CK-2A, qRDW.CK-2D , and qRDW.CK-3B , were selected for soil column culture (SC) trial to verify the effects of these QTLs under soil conditions. The RILs pyramiding the positive alleles not only had significantly higher shoot dry weight, RDW, nitrogen and phosphorus uptake in all the three treatments of the HC trial, but also had significantly higher RDW distribution in both the top- and sub-soils in the SC trial than those pyramiding the negative alleles. These results suggested that QTL analysis based on hydroponic culture can provide useful information for molecular design of wheat with large and deep root system. 17 A wheat MYB transcriptional repressor TaMyb1D regulates phenylpropanoid metabolism and enhances tolerance to drought and oxidative stresses in transgenic tobacco plants MYB transcription factors are involved in the regulation of plant development and response to biotic and abiotic stress. In this study, TaMyb1D, a novel subgroup 4 gene of the R2R3-MYB subfamily, was cloned from wheat (Triticum aestivum L.). TaMyb1D was localized in the nucleus and functioned as a transcriptional repressor. The overexpression of TaMyb1D in tobacco (Nicotiana tabacum) plants repressed the expression of genes related to phenylpropanoid metabolism and down-regulated the accumulation of lignin in stems and flavonoids in leaves. These changes affected plant development under normal conditions. The expression of TaMyb1D was ubiquitous and up-regulated by PEG6000 and H2O2 treatments in wheat. TaMyb1D-overexpressing transgenic tobacco plants exhibited higher relative water content and lower water loss rate during drought stress, as well as higher chlorophyll content in leaves during oxidative stress. The transgenic plants showed a lower leakage of ions as well as reduced malondialdehyde and H2O2 levels during conditions of drought and oxidative stresses. In addition, TaMyb1D up-regulated the expression levels of ROS- and stress-related genes in response to drought stress. Therefore, the overexpression of TaMyb1D enhanced tolerance to drought and oxidative stresses in tobacco plants. Our study demonstrates that TaMyb1D functions as a negative regulator of phenylpropanoid metabolism and a positive regulator of plant tolerance to drought and oxidative stresses. 18 Characterization of the CCT family and analysis of gene expression in Aegilops tauschii Flowering is crucial for reproductive success in flowering plant. The CCT domain-containing genes widely participate in the regulation of flowering process in various plant species. So far, the CCT family in common wheat is largely unknown. Here, we characterized the structure, organization, molecular evolution and expression of the CCT genes in Aegilops tauschii , which is the D genome donor of hexaploid wheat. Twenty-six CCT genes ( AetCCT ) were identified from the full genome of A . tauschii and these genes were distributed on all 7 chromosomes. Phylogenetic analysis classified these AetCCT genes into 10 subgroups. Thirteen AetCCT members in group A, C, H and G achieved rapid evolution based on evolutionary rate analysis. The AetCCT genes respond to different exogenous hormones and abiotic treatments, the expression of AetCCT4 , 7 , 8 , 11 , 12 , 16 , 17 , 19 , 21 and 22 showed a significant 24 h rhythm. This study may provide a reference for common wheat's evolution, domestication and evolvement rules, and also help us to understand the ecological adaptability of A . tauschii . 欢迎关注 小麦研究联盟 ，了解小麦新进展
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