WD40-REPEAT 5a functions in drought stress tolerance by regulating nitric oxide accumulation in Arabidopsis
WD40-REPEAT 5a functions in drought stress tolerance by regulating nitric oxide accumulation in Arabidopsis
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WD40-REPEAT 5a 通过调节拟南芥中一氧化氮的积累来发挥干旱胁迫耐受性
DOI：
10.1111/pce.12723
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发表时间：
2017-04-01
影响因子：
7.3
通讯作者：
Lu, Ying-Tang
中科院分区：
文献类型：
--
作者：
Liu, Wen-Cheng;Li, Yun-Hui;Lu, Ying-Tang
保卫细胞中一氧化氮合酶 (NOS) 产生的一氧化氮 (NO) 在植物对干旱胁迫的适应性反应的气孔关闭中起着至关重要的作用。然而，植物中 NOS 活性调节的机制尚不清楚。在这里，通过筛选在 H2O2 胁迫下 NO 积累和 NOS 样活性降低的酵母缺失突变体，我们确定 TUP1 是酵母中 NOS 样活性的新型调节剂。拟南芥 WD40-REPEAT 5a (WDR5a) 是酵母 TUP1 的同源物，可补充 H2O2 诱导的酵母突变体 tup1 的 NO 积累，表明 WDR5a 在调节 NO 积累和 NOS 样活性中的保守作用。通过使用拟南芥 RNAi 系 wdr5a-1 和 WDR5a 的两个 T-DNA 插入突变体（WDR5a 表达降低）进一步证实了这一点，其中 H2O2 诱导的 NO 积累和气孔关闭均受到抑制。这是因为与野生型相比，突变体中 H2O2 诱导的 NOS 样活性受到抑制。此外，这些 wdr5a 突变体对干旱胁迫更加敏感，因为它们减少了气孔关闭并减少了干旱相关基因的表达。总之，我们的结果表明，WDR5a 作为调节 NOS 样活性的新因子，可调节干旱胁迫耐受性中 NO 积累和气孔关闭的变化。
Nitric oxide (NO) generation by NO synthase (NOS) in guard cells plays a vital role in stomatal closure for adaptive plant response to drought stress. However, the mechanism underlying the regulation of NOS activity in plants is unclear. Here, by screening yeast deletion mutants with decreased NO accumulation and NOS-like activity when subjected to H2O2 stress, we identified TUP1 as a novel regulator of NOS-like activity in yeast. Arabidopsis WD40-REPEAT 5a (WDR5a), a homolog of yeast TUP1, complemented H2O2-induced NO accumulation of a yeast mutant tup1, suggesting the conserved role of WDR5a in regulating NO accumulation and NOS-like activity. This note was further confirmed by using an Arabidopsis RNAi line wdr5a-1 and two T-DNA insertion mutants of WDR5a with reduced WDR5a expression, in which both H2O2-induced NO accumulation and stomatal closure were repressed. This was because H2O2-induced NOS-like activity was inhibited in the mutants compared with that of the wild type. Furthermore, these wdr5a mutants were more sensitive to drought stress as they had reduced stomatal closure and decreased expression of drought-related genes. Together, our results revealed that WDR5a functions as a novel factor to modulate NOS-like activity for changes of NO accumulation and stomatal closure in drought stress tolerance.