2013年10月3日刘玉乐教授研究组在PLoS Pathogens上在线发表了题为“Type I J-domain NbMIP1 proteins are required for both Tobacco Mosaic Virus infection and plant innate immunity”的研究论文,报道发现J结构域蛋白MIP1不仅对植物病毒侵染是必需的,而且对多种植物抗病途径也是必需的,是目前发现的最重要的植物抗病信号分子之一。
番茄花叶病毒(ToMV)和烟草花叶病毒(TMV)可在番茄等重要经济作物上引起严重病害。Tm-22是CC-NBS-LRR类的抗性蛋白,它通过识别ToMV以及TMV的运动蛋白(MP)诱导植物产生抗病反应。目前对Tm-22介导植物抗病反应的机制了解很少。
该工作鉴定了既与ToMV MP相互作用,又与Tm-22相互作用的一组Ⅰ型J蛋白MIP1。 沉默MIP1降低TMV的细胞间运动和系统运动;令人惊讶的是:沉默MIP1也导致Tm-22介导的病毒抗性的丧失。这些结果表明MIP1不仅对病毒侵染是必需的,而且对Tm-22介导的植物抗病毒也是必需的。进一步发现:MIP1对N基因介导的植物病毒抗性,Pto介导的基因介导的植物细菌抗性,Cf9基因介导的植物真菌抗性和非寄主病原Pst DC3000诱导的非寄主抗性也是必需的。该工作还发现,沉默NbMIP1能够导致ToMV MP和Tm-22蛋白水平的显著降低,但不影响它们的转录。此外,还发现植物抗性信号分子SGT1也与MIP1互作并参与Tm-22介导的抗病反应。这些研究表明:MIP1可能与SGT1一起作为辅助伴侣分子(co-chaperone)通过帮助病毒蛋白和植物抗病蛋白的正确折叠和成熟而参与病毒侵染和植物抗病反应。
这是刘玉乐教授研究组2013年在Molecular Plant、Plant Physiology、Plant Cell、Autophagy上相继发表植物免疫及细胞自噬重要研究进展后的又一重要发现。清华大学生命学院08级博士生杜玉梅、博士后赵晋平和11级博士生陈天元是本文的共同第一作者,刘玉乐教授是本文的通讯作者。(生物谷Bioon.com)
生物谷推荐的英文摘要
PLoS Pathogens doi:10.1371/journal.ppat.1003659
Type I J-Domain NbMIP1 Proteins Are Required for Both Tobacco Mosaic Virus Infection and Plant Innate Immunity
Yumei Du equal, Jinping Zhao equal, Tianyuan Chen equal contributor, Qi Liu, Haili Zhang, Yan Wang, Yiguo Hong, Fangming Xiao, Ling Zhang, Qianhua Shen, Yule Liu mail
Tm-22 is a coiled coil-nucleotide binding-leucine rich repeat resistance protein that confers durable extreme resistance against Tomato mosaic virus (ToMV) and Tobacco mosaic virus (TMV) by recognizing the viral movement protein (MP). Here we report that the Nicotiana benthamiana J-domain MIP1 proteins (NbMIP1s) associate with tobamovirus MP, Tm-22 and SGT1. Silencing of NbMIP1s reduced TMV movement and compromised Tm-22-mediated resistance against TMV and ToMV. Furthermore, silencing of NbMIP1s reduced the steady-state protein levels of ToMV MP and Tm-22. Moreover, NbMIP1s are required for plant resistance induced by other R genes and the nonhost pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. In addition, we found that SGT1 associates with Tm-22 and is required for Tm-22-mediated resistance against TMV. These results suggest that NbMIP1s function as co-chaperones during virus infection and plant immunity.