Jasmonates (JAs), a class of lipid-derived stress hormones, play a crucial role across an array of plant physiological processes and stress responses. Although JA signaling is thought to rely predominantly on the degradation of specific JAZ proteins by SCF, it remains unclear whether other pathways are involved in the regulation of JAZ protein stability. Here, we report that PUB22, a plant U-box type E3 ubiquitin ligase, plays a critical role in the regulation of plant resistance against and other JA responses in tomato. Whereas COI1 physically interacts with JAZ1/2/5/7, PUB22 physically interacts with JAZ1/3/4/6. PUB22 ubiquitinates JAZ4 to promote its degradation via the 26S proteasome pathway. Importantly, we observed that mutants showreduced resistance to whereas single mutants and quadruple mutants have enhanced resistance. The hypersensitivity of mutants to herbivores could be partially rescued by mutation. Moreover, we found that expression of can be transcriptionally activated by MYC2, thus forming a positive feedback circuit in JA signaling. We noticed that the PUB22–JAZ4 module also regulates other JA responses, including defense against , inhibition of root elongation, and anthocyanin accumulation. Taken together, these results indicate that PUB22 plays a crucial role in plant growth and defense responses, together with COI1-regulated JA signaling, by targeting specific JAZs.

中文翻译：

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MYC2–PUB22–JAZ4 模块在番茄茉莉酸信号传导中发挥着至关重要的作用

茉莉酸 (JAs) 是一类脂质衍生的应激激素，在一系列植物生理过程和应激反应中发挥着至关重要的作用。尽管 JA 信号传导被认为主要依赖于 SCF 对特定 JAZ 蛋白的降解，但尚不清楚其他途径是否参与 JAZ 蛋白稳定性的调节。在这里，我们报道 PUB22，一种植​​物 U 盒型 E3 泛素连接酶，在调节番茄植物抗 JA 反应和其他 JA 反应中发挥着关键作用。 COI1 与 JAZ1/2/5/7 物理相互作用，而 PUB22 与 JAZ1/3/4/6 物理相互作用。 PUB22 泛素化 JAZ4，通过 26S 蛋白酶体途径促进其降解。重要的是，我们观察到突变体表现出较低的抗性，而单突变体和四重突变体则具有增强的抗性。突变体对食草动物的过敏可以通过突变得到部分缓解。此外，我们发现 的表达可以被 MYC2 转录激活，从而在 JA 信号传导中形成正反馈回路。我们注意到 PUB22-JAZ4 模块还调节其他 JA 反应，包括防御、抑制根伸长和花青素积累。综上所述，这些结果表明 PUB22 通过靶向特定的 JAZ，与 COI1 调节的 JA 信号传导一起在植物生长和防御反应中发挥着至关重要的作用。