Zhu Dongmei, Hu Shuai, Cao Wenhan, Gao Yanli, Li Yan, Xu Juan, Li Baiying, Jiang Liwen, Rojo Enrique, Shen Jinbo
National Key Laboratory for Development and Utilization of Forest Food Resources, Zhejiang A&F University, Hangzhou, China.
Provincial Key Laboratory for Non-wood Forest and Quality Control and Utilization of Its Products, Zhejiang A&F University, Hangzhou, China.
Nat Plants. 2025 Aug 18. doi: 10.1038/s41477-025-02077-8.
Vacuolar sorting receptors (VSRs) are involved in sorting soluble vacuolar proteins during normal plant growth and development, but their role in plant stress responses remains largely unexplored. Here we report that a subgroup of the Arabidopsis thaliana VSR genes are transcriptionally induced during infection with avirulent Pseudomonas syringae strains, leading to higher VSR protein accumulation. We demonstrate that the pathogen-responsive VSR1, VSR5, VSR6 and VSR7 genes function redundantly in sorting vacuolar death-related enzymes induced during bacterial infection. Moreover, VSRs are required for fusion of the tonoplast with the plasma membrane and the subsequent release of vacuolar contents into the apoplast, where bacterial pathogens reside. Indeed, dysfunction of this subgroup of VSRs blocks hypersensitive cell death and leads to stronger disease symptoms and higher bacterial loads, revealing their essential role in defence against avirulent bacterial infection. Intriguingly, their disruption also leads to defects in autophagy, impairing autophagosome-mediated degradation of bacterial effector proteins. Collectively, our results show that VSR1, VSR5, VSR6 and VSR7 are key regulators of plant effector-triggered immunity (ETI) by orchestrating receptor-mediated vacuolar sorting of immunity-related proteins, tonoplast to plasma membrane fusion, and autophagic degradation of effector proteins.
液泡分选受体（VSRs）在正常植物生长发育过程中参与可溶性液泡蛋白的分选，但它们在植物应激反应中的作用仍 largely 未被探索。在这里我们报告，拟南芥 VSR 基因的一个亚组在无毒丁香假单胞菌菌株感染期间被转录诱导，导致 VSR 蛋白积累增加。我们证明，病原体响应性的 VSR1、VSR5、VSR6 和 VSR7 基因在分选细菌感染期间诱导的液泡死亡相关酶方面发挥冗余功能。此外，VSRs 是液泡膜与质膜融合以及随后将液泡内容物释放到细菌病原体所在的质外体所必需的。实际上，这一 VSR 亚组的功能障碍会阻止超敏细胞死亡，并导致更强的疾病症状和更高的细菌载量，揭示了它们在抵御无毒细菌感染中的重要作用。有趣的是，它们的破坏还会导致自噬缺陷，损害自噬体介导的细菌效应蛋白降解。总的来说，我们的结果表明，VSR1、VSR5、VSR6 和 VSR7 通过协调受体介导的免疫相关蛋白的液泡分选、液泡膜到质膜融合以及效应蛋白的自噬降解，是植物效应物触发免疫（ETI）的关键调节因子。
