The WRKY70 transcription factor: A node of convergence for jasmonate-mediated and salicylate-mediated signals in plant defense
The WRKY70 transcription factor: A node of convergence for jasmonate-mediated and salicylate-mediated signals in plant defense
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DOI：
10.1105/tpc.016980
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发表时间：
2004-02-01
期刊：
影响因子：
11.6
通讯作者：
Palva, ET
中科院分区：
文献类型：
--
作者：
Li, J;Brader, G;Palva, ET
水杨酸(SA)-和茉莉酸(JA)-依赖的防御信号之间的串扰已经在植物中得到了很好的记录，但这种串扰是如何执行的以及所涉及的成分仍有待阐明。我们证明了植物特异性转录因子WRKY70是SA和ja介导的信号通路的共同组成部分。WRKY70的表达受SA激活，受JA抑制。SA对WRKY70的早期诱导与NPR1无关，但全面诱导需要功能性的NPR1。上位分析表明，WRKY70在sa依赖的信号通路中位于NPR1的下游。通过组成性过表达调节WRKY70转录物水平，增加了对毒性病原体的抗性，并导致sa诱导的发病相关基因的组成性表达。相反，WRKY70的反义抑制会激活ja响应/ coi1依赖基因。WRKY70的作用不是由随后SA或JA水平的变化引起的。我们认为WRKY70可以作为sa诱导基因的激活因子和ja应答基因的抑制因子，整合来自这些相互拮抗途径的信号。
Cross talk between salicylic acid (SA)- and jasmonic acid (JA)-dependent defense signaling has been well documented in plants, but how this cross talk is executed and the components involved remain to be elucidated. We demonstrate that the plant-specific transcription factor WRKY70 is a common component in SA- and JA-mediated signal pathways. Expression of WRKY70 is activated by SA and repressed by JA. The early induction of WRKY70 by SA is NPR1-independent, but functional NPR1 is required for full-scale induction. Epistasis analysis suggested that WRKY70 is downstream of NPR1 in an SA-dependent signal pathway. Modulation of WRKY70 transcript levels by constitutive overexpression increases resistance to virulent pathogens and results in constitutive expression of SA-induced pathogenesis-related genes. Conversely, antisense suppression of WRKY70 activates JA-responsive/COI1-dependent genes. The effect of WRKY70 is not caused by subsequent changes in SA or JA levels. We suggest that WRKY70 acts as an activator of SA-induced genes and a repressor of JA-responsive genes, integrating signals from these mutually antagonistic pathways.