Arabidopsis EARLY FLOWERING3 increases salt tolerance by suppressing salt stress response pathways

Corresponding author: Nam-Chon Paek

Arabidopsis EARLY FLOWERING3 (ELF3) functions in modulating light input to the circadian clock (生物钟), as a component of ELF3-ELF4-LUX ARRHYTHMO (LUX) evening complex. However, the role of ELF3 in stress responses remains largely unknown. In this study, we show that ELF3 enhances plants’ resilience (快速恢复的能力) to salt stress: ELF3-overexpressing (ELF3-OX) plants are salt-tolerant, while elf3 mutants are more sensitive to salt stress. The expressions of many salt stress- and senescence-associated genes (衰老相关基因) are altered in elf3-1 and ELF3-OX plants compared with wild-type. During salt stress, ELF3 suppresses factors that promote salt stress response pathways, mainly GIGANTEA (GI), at the post-translational level (翻译后水平), and PHYTOCHROME INTERACTING FACTOR4 (PIF4), at the transcriptional level (转录水平). To enhance the salt stress response, PIF4 directly downregulates the transcription of JUNGBRUNNEN1 (JUB1/ANAC042), encoding a transcription factor that upregulates the expression of stress tolerance genes, DREB2A and DELLA. Furthermore, PIF4 directly upregulates the transcription of ORESARA1 (ORE1/ANAC092) and SAG29, positive regulators of salt stress response pathways. Based on our results, we propose that ELF3 modulates key regulatory components in salt stress response pathways at the transcriptional and post-translational levels.

拟南芥ELF3作用于调节生物钟的光摄入，是ELF3-ELF4-LUX ARRHYTHMO即LUX夜间复合物的组分。然而ELF3在胁迫响应中的作用还不清楚。本文的研究显示ELF3增强植物在盐胁迫下的恢复，过表达ELF3植株具有耐盐性，而elf3突变体则对盐胁迫更加敏感。与野生型相比，elf3突变体和ELF3过表达植株在许多盐胁迫和衰老相关基因的表达均有所改变。在盐胁迫条件下，ELF3会从翻译后水平抑制GI和转录水平抑制PIF4，而这些因子会促进盐胁迫的响应通路。PIF4会直接下调JUB1/ANAC042的转录以增强盐胁迫响应，而JUB1/ANAC042基因编码一个上调胁迫抗性基因DREB2A和DELLA的转录因子。此外，PIF4会直接上调ORESARA1和SAG29的转录，这两个基因是盐胁迫响应通路的正向调控子。基于这些结果，作者认为ELF3在转录及翻译后水平调控盐胁迫响应通路的关键调控组分。

研究方向： 作物分子遗传。

doi: 10.1111/tpj.13747