Plant Journal：浙大生科院植物所郑绍建教授实验室发表水分对植物

摘要 : 近日植物学顶级期刊The Plant Journal发表浙大生科院植物所郑绍建教授实验室发表植物论文。博士后丁忠杰博士和博士生颜晶莹为该论文的共同第一作者。


近日植物学顶级期刊The plant Journal发表浙大生科院植物所郑绍建教授实验室发表植物论文。博士后丁忠杰博士和博士生颜晶莹为该论文的共同第一作者。

根系是植物吸收营养的主要器官，而侧根发育在很大程度上决定了根系的形态结构以及植物从土壤吸收水分和养分的能力。在中度及以上的干旱、盐等水分胁迫下，植物的侧根发育往往受到了严重的抑制。这种抑制主要由脱落酸(ABA)以及非ABA途径介导。然而水分胁迫下根系发育的分子机制仍不清楚。这里我们发现，水分胁迫对侧根的抑制是一种动态的平衡。一方面，水分胁迫诱导植物体内ABA的产生，从而抑制侧根发育;另一方面，水分胁迫又以非ABA途径维持转录因子WRKY46的表达，从而促进侧根发育。ABA能够显著抑制WRKY46在根系中的表达，而WRKY46又通过promoter-binding抑制ABA信号途径关键调控因子ABI4的表达。因此，ABA和WRKY46介导了两条相互拮抗的信号途径，并最终通过影响体内Auxin的内稳态，共同调控植物侧根在水分胁迫下的发育。

原文链接：

Transcription factor WRKY46 modulates the development of Arabidopsis lateral roots in osmotic/salt stress conditions via regulation of ABA signaling and auxin homeostasis

原文摘要：

The development of lateral roots (LR) is known to be severely inhibited by salt or osmotic stress. However, the molecular mechanisms underlying LR development in osmotic/salt stress conditions are poorly understood. Here we show that the gene encoding the WRKY transcription factor WRKY46 (WRKY46) is expressed throughout lateral root primordia (LRP) during early LR development and that expression is subsequently restricted to the stele of the mature LR. In osmotic/salt stress conditions, lack of WRKY46 (in loss-of-function wrky46 mutants) significantly reduces, while overexpression of WRKY46 enhances LR development. We also show that exogenous auxin largely restores LR development in wrky46 mutants, and that the auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) inhibits LR development in both wild-type (WT; Col-0) and in a line overexpressing WRKY46 (OV46). Subsequent analysis of abscisic acid (ABA)-related mutants indicated thatWRKY46 expression is down-regulated by ABA signaling, and up-regulated by an ABA-independent signal induced by osmotic/salt stress. Next, we show that expression of the DR5:GUS auxin response reporter is reduced in roots of wrky46 mutants, and that both wrky46 mutants and OV46 display altered root levels of free indole-3-acetic acid (IAA) and IAA conjugates. Subsequent RT-qPCR and ChIP-qPCR experiments indicated that WRKY46 directly regulates the expression of ABI4and of genes regulating auxin conjugation. Finally, analysis of wrky46 abi4 double mutant plants confirms that ABI4 acts downstream of WRKY46. In summary, our results demonstrate that WRKY46 contributes to the feedforward inhibition of osmotic/salt stress-dependent LR inhibition via regulation of ABA signaling and auxin homeostasis.

doi: 10.1111/tpj.12958

作者：郑绍建教授

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