Salicylic acid-mediated innate immunity in Arabidopsis is regulated by SIZ1 SUMO E3 ligase
Salicylic acid-mediated innate immunity in Arabidopsis is regulated by SIZ1 SUMO E3 ligase
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DOI：
10.1111/j.1365-313x.2006.02947.x
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发表时间：
2007-01-01
期刊：
影响因子：
7.2
通讯作者：
Yun, Dae-Jin
中科院分区：
文献类型：
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作者：
Lee, Jiyoung;Nam, Jaesung;Yun, Dae-Jin
小泛素样修饰物（SUMO）蛋白对靶蛋白的可逆修饰参与了酵母和动物的许多细胞过程。然而，我们对植物中sumoylation的功能知之甚少。在这里，我们发现编码拟南芥SUMO E3连接酶的SIZ1基因调节先天免疫。突变体siz1植株表现出组成性系统获得性抗性（SAR），其特征是水杨酸（SA）积累增加，致病相关基因（PR）表达增加，对紫丁香假单胞菌pv的抗性增强。番茄（Pst） DC3000。将NahG基因转移到大小为1的植株上，可使这些表型逆转回野生型。对双突变体npr1 siz1、pad4 siz1和ndr1 siz1的分析表明，siz1控制SA信号传导。SIZ1通过上位性与PAD4相互作用调控PR表达和抗病性。与这些观察结果一致，siz1植物对表达avrRps4的Pst DC3000的抗性增强，avrRps4是一种细菌无毒决定因素，对EDS1/ pad4依赖的TIR-NBS-type R基因有反应。相比之下，siz1植株对表达avrRpm1的Pst DC3000没有抗性，avrRpm1是一种细菌毒性决定因子，对ndr1依赖性CC-NBS-type R基因有应答。茉莉酸（Jasmonic acid， JA）诱导的PDF1.2表达和对灰霉病的敏感性在1号植株中没有变化。综上所述，这些结果表明，SIZ1是SA和pad4介导的R基因信号传导所必需的，而这反过来又赋予拟南芥先天免疫。
Reversible modifications of target proteins by small ubiquitin-like modifier (SUMO) proteins are involved in many cellular processes in yeast and animals. Yet little is known about the function of sumoylation in plants. Here, we show that the SIZ1 gene, which encodes an Arabidopsis SUMO E3 ligase, regulates innate immunity. Mutant siz1 plants exhibit constitutive systemic-acquired resistance (SAR) characterized by elevated accumulation of salicylic acid (SA), increased expression of pathogenesis-related (PR) genes, and increased resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Transfer of the NahG gene to siz1 plants results in reversal of these phenotypes back to wild-type. Analyses of the double mutants, npr1 siz1, pad4 siz1 and ndr1 siz1 revealed that SIZ1 controls SA signalling. SIZ1 interacts epistatically with PAD4 to regulate PR expression and disease resistance. Consistent with these observations, siz1 plants exhibited enhanced resistance to Pst DC3000 expressing avrRps4, a bacterial avirulence determinant that responds to the EDS1/PAD4-dependent TIR-NBS-type R gene. In contrast, siz1 plants were not resistant to Pst DC3000 expressing avrRpm1, a bacterial avirulence determinant that responds to the NDR1-dependent CC-NBS-type R gene. Jasmonic acid (JA)-induced PDF1.2 expression and susceptibility to Botrytis cinerea were unaltered in siz1 plants. Taken together, these results demonstrate that SIZ1 is required for SA and PAD4-mediated R gene signalling, which in turn confers innate immunity in Arabidopsis.