Regulation of plant immunity through ubiquitin-mediated modulation of Ca(2+) -calmodulin-AtSR1/CAMTA3 signaling.
Regulation of plant immunity through ubiquitin-mediated modulation of Ca(2+) -calmodulin-AtSR1/CAMTA3 signaling.
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DOI：
10.1111/tpj.12473
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
Lei Zhang;Liqun Du;Liqun Du;Chenjia Shen;Chenjia Shen;Yanjun Yang;Yanjun Yang;B. Poovaiah
中科院分区：
文献类型：
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作者：
Lei Zhang;Liqun Du;Liqun Du;Chenjia Shen;Chenjia Shen;Yanjun Yang;Yanjun Yang;B. Poovaiah
细胞内Ca（2+）浓度的瞬时变化是激活植物免疫的重要信号。Ca（2+）信号通过AtSR 1/CAMTA 3抑制水杨酸介导的植物防御，AtSR 1/CAMTA 3是Ca（2+）/钙调素调节的转录因子家族的成员，在多细胞真核生物中是保守的。植物如何克服这种负调节，在胞内Ca（2+）激增阶段进行有效的防御反应尚不清楚。在这里，我们报告的一个重要组成部分的泛素连接酶的识别和功能特性，以及相关的AtSR 1营业额。AtSR 1相互作用蛋白1（SR 1 IP 1）通过CytoTrap双杂交筛选得到。SR 1 IP 1的功能丧失突变体对细菌病原体更敏感，并且SR 1 IP 1的过表达赋予增强的抗性，表明SR 1 IP 1充当植物防御的正调节剂。SR 1 IP 1和AtSR 1通过相同的信号通路调节植物免疫。SR 1 IP 1包含基于cullin 3的E3泛素连接酶的底物适配器的结构特征，并且被证明作为底物适配器，当植物受到病原体的挑战时，其招募AtSR 1用于泛素化和降解。因此，SR 1 IP 1通过去除防御抑制因子AtSR 1来积极调节植物免疫。这些发现提供了一个机制的洞察，如何协调钙（2+）介导的行动，以实现有效的植物免疫。
Transient changes in intracellular Ca(2+) concentration are essential signals for activation of plant immunity. It has also been reported that Ca(2+) signals suppress salicylic acid-mediated plant defense through AtSR1/CAMTA3, a member of the Ca(2+) /calmodulin-regulated transcription factor family that is conserved in multicellular eukaryotes. How plants overcome this negative regulation to mount an effective defense response during a stage of intracellular Ca(2+) surge is unclear. Here we report the identification and functional characterization of an important component of ubiquitin ligase, and the associated AtSR1 turnover. The AtSR1 interaction protein 1 (SR1IP1) was identified by CytoTrap two-hybrid screening. The loss-of-function mutant of SR1IP1 is more susceptible to bacterial pathogens, and over-expression of SR1IP1 confers enhanced resistance, indicating that SR1IP1 acts as a positive regulator of plant defense. SR1IP1 and AtSR1 act in the same signaling pathway to regulate plant immunity. SR1IP1 contains the structural features of a substrate adaptor in cullin 3-based E3 ubiquitin ligase, and was shown to serve as a substrate adaptor that recruits AtSR1 for ubiquitination and degradation when plants are challenged with pathogens. Hence, SR1IP1 positively regulates plant immunity by removing the defense suppressor AtSR1. These findings provide a mechanistic insight into how Ca(2+) -mediated actions are coordinated to achieve effective plant immunity.