Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry of Ministry of Education, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China.
Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
Biochem Biophys Res Commun. 2024 Jan 1;690:149256. doi: 10.1016/j.bbrc.2023.149256. Epub 2023 Nov 17.
14-3-3 proteins play important roles in plant metabolism and stress response. Tomato 14-3-3 proteins, SlTFT4 and SlTFT7, serve as hubs of plant immunity and are targeted by some pathogen effectors. Ralstonia solanacearum with more than 70 type Ⅲ effectors (T3Es) is one of the most destructive plant pathogens. However, little is known on whether R. solanacearum T3Es target SlTFT4 and SlTFT7 and hence interfere with plant immunity. We first detected the associations of SlTFT4/SlTFT7 with R. solanacearum T3Es by luciferase complementation assay, and then confirmed the interactions by yeast two-hybrid approach. We demonstrated that 22 Ralstonia T3Es were associated with both SlTFT4 and SlTFT7, and five among them suppressed the hypersensitive response induced by MAPKKKα, a protein kinase which associated with SlTFT4/SlTFT7. We further demonstrated that suppression of MAPKKKα-induced HR and plant basal defense by the T3E RipAC depend on its association with 14-3-3 proteins. Our findings firstly demonstrate that R. solanacearum T3Es can manipulate plant immunity by targeting 14-3-3 proteins, SlTFT4 and SlTFT7, providing new insights into plant-R. solanacearum interactions.
14-3-3 蛋白在植物代谢和应激反应中发挥着重要作用。番茄 14-3-3 蛋白 SlTFT4 和 SlTFT7 作为植物免疫的枢纽，被一些病原体效应子靶向。茄青枯雷尔氏菌（Ralstonia solanacearum）拥有超过 70 种 III 型效应子（T3Es），是最具破坏性的植物病原体之一。然而，目前还不清楚茄青枯雷尔氏菌 T3Es 是否靶向 SlTFT4 和 SlTFT7 并干扰植物免疫。我们首先通过荧光素酶互补测定法检测了 SlTFT4/SlTFT7 与茄青枯雷尔氏菌 T3Es 的关联，然后通过酵母双杂交法进一步证实了它们之间的相互作用。结果表明，22 种茄青枯雷尔氏菌 T3Es 与 SlTFT4 和 SlTFT7 都有关联，其中 5 种 T3Es 抑制了与 SlTFT4/SlTFT7 相关的蛋白激酶 MAPKKKα 诱导的过敏反应。我们进一步证实，T3E RipAC 通过与 14-3-3 蛋白相互作用来抑制由 MAPKKKα 诱导的 HR 和植物基础防御。我们的研究结果首次表明，茄青枯雷尔氏菌 T3Es 可以通过靶向 14-3-3 蛋白 SlTFT4 和 SlTFT7 来操纵植物免疫，为植物与茄青枯雷尔氏菌的相互作用提供了新的见解。
