State Key Laboratory of Rice Biology, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Mol Plant Pathol. 2023 Nov;24(11):1359-1369. doi: 10.1111/mpp.13373. Epub 2023 Jul 5.
Our previous study identified an evolutionarily conserved C4HC3-type E3 ligase, named microtubule-associated E3 ligase (MEL), that regulates broad-spectrum plant resistance against viral, fungal and bacterial pathogens in multiple plant species by mediating serine hydroxymethyltransferase (SHMT1) degradation via the 26S proteasome pathway. In the present study, we found that NS3 protein encoded by rice stripe virus could competitively bind to the MEL substrate recognition site, thereby inhibiting MEL interacting with and ubiquitinating SHMT1. This, in turn, leads to the accumulation of SHMT1 and the repression of downstream plant defence responses, including reactive oxygen species accumulation, mitogen-activated protein kinase pathway activation, and the up-regulation of disease-related gene expression. Our findings shed light on the ongoing arms race between pathogens and demonstrate how a plant virus can counteract the plant defence response.
我们之前的研究发现了一个进化上保守的 C4HC3 型 E3 连接酶，命名为微管相关 E3 连接酶（MEL），它通过介导丝氨酸羟甲基转移酶 1（SHMT1）的降解来调节多种植物物种对病毒、真菌和细菌病原体的广谱植物抗性，该过程通过 26S 蛋白酶体途径进行。在本研究中，我们发现水稻条纹病毒编码的 NS3 蛋白可以与 MEL 底物识别位点竞争结合，从而抑制 MEL 与 SHMT1 相互作用和泛素化。这反过来又导致 SHMT1 的积累和下游植物防御反应的抑制，包括活性氧物质的积累、丝裂原活化蛋白激酶途径的激活以及与疾病相关基因表达的上调。我们的研究结果揭示了病原体之间正在进行的军备竞赛，并展示了植物病毒如何对抗植物防御反应。
