Silencing of G proteins uncovers diversified plant responses when challenged by three elicitors in Nicotiana benthamiana.
Silencing of G proteins uncovers diversified plant responses when challenged by three elicitors in Nicotiana benthamiana.
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DOI：
10.1111/j.1365-3040.2011.02417.x
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Huajian Zhang;Mei-Mei Wang-Mei;Wei Wang;Deqing Li;Qian Huang;Yuanchao Wang;Xiaobo Zheng;Zhengguang Zhang
中科院分区：
文献类型：
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作者：
Huajian Zhang;Mei-Mei Wang-Mei;Wei Wang;Deqing Li;Qian Huang;Yuanchao Wang;Xiaobo Zheng;Zhengguang Zhang
通过由α-、β-和γ-亚基组成的异源三聚体G蛋白的信号传导在许多生理过程中是必不可少的。在这里，我们表明，这种典型的G蛋白复合物的作用机制，通过控制激发子对过敏反应（HR）和气孔关闭烟草。使用病毒诱导的基因沉默产生Gα-、Gβ1-和Gβ2-沉默的植物。所有沉默的植物分别用黄单胞菌属（Xanthomonasseiharpin）、稻瘟菌属（MagnaportheBoehmeriae）Nep 1和苎麻疫霉（Phytophthoraboehmeriae）处理。在用harpin处理的Gα和Gβ2沉默的植物中，HR显著受损，表明harpin而不是Nep 1或boehmerin触发的HR是Gα和Gβ2依赖的。此外，所有Gα、Gβ1和Gβ2基因沉默的植株均显著抑制了诱导子诱导的气孔关闭、诱导子促进的保卫细胞一氧化氮（NO）生成和活性氧的积累。据我们所知，这是首次报道Gα和Gβ亚基参与气孔关闭响应激发子。此外，Gα、Gβ1和Gβ2基因的沉默对植物防御相关基因在三种激发子攻击下的转录也有影响。总之，G蛋白亚基的沉默导致许多有趣的植物细胞反应，揭示了植物免疫系统采用保守的和不同的G蛋白途径来感知来自植物微生物进化过程中形成的不同植物病原体的激发子。
Signalling through heterotrimeric G protein composed of α-, β- and γ-subunits is essential in numerous physiological processes. Here we show that this prototypical G protein complex acts mechanistically by controlling elicitor sensitivity towards hypersensitive response (HR) and stomatal closure in Nicotiana benthamiana. Gα-, Gβ1-, and Gβ2-silenced plants were generated using virus-induced gene silencing. All silenced plants were treated with Xanthomonas oryzae harpin, Magnaporthe oryzae Nep1 and Phytophthora boehmeriae boehmerin, respectively. HR was dramatically impaired in Gα- and Gβ2-silenced plants treated with harpin, indicating that harpin-, rather than Nep1- or boehmerin-triggered HR, is Gα- and Gβ2-dependent. Moreover, all Gα-, Gβ1- and Gβ2-silenced plants significantly impaired elicitor-induced stomatal closure, elicitor-promoted nitric oxide (NO) production and active oxygen species accumulation in guard cells. To our knowledge, this is the first report of Gα and Gβ subunits involvement in stomatal closure in response to elicitors. Furthermore, silencing of Gα, Gβ1 and Gβ2 has an effect on the transcription of plant defence-related genes when challenged by three elicitors. In conclusion, silencing of G protein subunits results in many interesting plant cell responses, revealing that plant immunity systems employ both conserved and distinct G protein pathways to sense elicitors from distinct phytopathogens formed during plant-microbe evolution.