背景回顾：Leaves are strikingly diverse in terms of shapes and complexity. The wild and cultivated strawberry plants mostly develop trifoliate compound leaves, yet the underlying genetic basis remains unclear in this important fruit crop in Rosaceae. 

主要发现：Here, we identified two EMS mutants designated simple leaf1 (sl1-1, sl1-2) and one natural simple-leafed mutant monophylla in Fragaria vesca. Their causative mutations all reside in SL1 (FvH4_7g28640) causing premature stop codon at different positions in sl1-1 and sl1-2 and an eight-nucleotide insertion (GTTCATCA) in monophylla. 

结果1-SL1基因功能：SL1 encodes a transcription regulator with the conserved DNA binding domain GT-1 and the catalytic domain of protein kinases PKc. Expression of SL1pro::SL1 in sl1-1 completely restored compound leaf formation. The 35S::SL1 lines developed palmate-like leaves with four or five leaflets at a low penetrance. 

结果2-作用方式：However, overexpressing the truncated SL1ΔPK caused no phenotypes, probably due to the disruption of homo-dimerization. 

结果3-表达模式：SL1 is preferentially expressed at the tips of leaflets and serrations. 

结果4-作用途径：Moreover, SL1 is closely associated with the auxin pathway and works synergistically with FveLFYa in leaf morphogenesis. 

结论：Overall, our work uncovered a new type of transcription regulator that promotes compound leaf formation in the woodland strawberry, and shed new lights on the diversity of the leaf complexity control.

 摘 要 

植物叶片就其形状和复杂性上来说是十分多样化的。野生和栽培种草莓通常会发育出三出复叶，但是潜在的分子调控机制仍不清楚。本文中，作者在野草莓中通过EMS诱变筛选出两个三出复叶转变为单叶的突变株sl1-1和sl1-2，以及一个天然的单叶突变体。这三个突变体的突变位点都位于SL1基因内，其中sl1-1和sl1-2突变导致了该基因在不同的位置发生提前终止，而自然单叶突变体则引入了一个八核甘酸的插入。SL1编码一个转录调控子，具有保守的DNA结合域GT-1和蛋白激酶催化域PKc。在sl1-1突变体中表达SL1pro::SL1能够完全恢复复叶的形成。35S::SL1过表达株系发育出类似于掌状复叶的叶片，存在四至五片小叶，但是出现该表型的比例较低。但是，过表达截短的SL1基因SL1ΔPK会导致没有明显的表型变化，可能是由于未形成同源二聚体。SL1优先在小叶和锯齿的顶端表达。此外，SL1与生长素途径相关，并且与FveLFYa协同于叶片形态发生。综上，本文的研究揭示了一个新的转录调控因子作用于林地草莓复杂叶片的形成，为叶片复杂性调控的多样性提供了新的视野。

** 康春颖 **