番茄斑萎病毒NSm蛋白与本氏烟光系统-I组成亚基TMP14直接互作的分子机制

Chloroplast, a pivotal organelle for photosynthesis occurs in higher plants, plays fundamental roles in life cycles of some plant viruses. Numbers of chloroplast associated proteins have been identified to interact with viral proteins. However, TMP14, a subunit of photosystem I in chloroplast has never been found to interact with any viral protein to date. Upon the investigation of Tomato spotted wilt virus (TSWV), one of the most destructive plant viruses in the world, the TSWV-encoded protein NSm was found to interact with the Nicotiana benthamiana TMP14 (NbTMP14). To unravel the molecular bases of this novel protein-protein interaction, the study will be performed as follows: 1) further verification of the TSWV NSm-NbTMP14 interaction; 2) mapping of the interacting domain(s) as well as the key amino acid(s) responsible for the TSWV NSm-NbTMP14 interaction; 3) characterization of the sublocalization of NbTMP14 upon interacting with the TSWV NSm, 4) functional analysis of the TSWV NSm-NbTMP14 interaction in the viral life cycle. The study aims at one of the research focuses in plant virology as well as the current urgent issue in agriculture. The expected result will not only be in favour of unraveling the possible mechanism of pathogenesis of TSWV, providing new insights in strategies for molecular breeding of anti-TSWV crop, but also promote a better understanding of the biological roles of the chloroplast in the plant virus-host interactions.

叶绿体是植物进行光合作用的关键细胞器，在植物病毒的生命周期中同样具有重要作用。迄今已发现多种叶绿体相关蛋白与病毒编码蛋白直接互作，但尚没有叶绿体光系统-I组成亚基TMP14与任何病毒蛋白互作的报道。申请者以当前农业生产中一种极具毁灭性的植物病毒--番茄斑萎病毒（TSWV）为研究对象，首次发现TSWV编码蛋白NSm与本氏烟NbTMP14直接互作。本项目拟针对这一新型未知的互作关系展开，1）进一步验证TSWV NSm-NbTMP14互作， 2）确定介导蛋白互作的结合域及关键氨基酸，3）分析互作对NbTMP14胞内定位的影响，4）探明互作在TSWV生命周期中的生物学意义。研究内容紧密围绕病毒学领域的研究热点和当前农业生产的迫切需求。研究结果不仅有助于揭示TSWV的致病机理，为作物抗TSWV的分子育种提供新思路，同时也将为全面了解叶绿体在植物病毒-寄主互作中的作用提供更多的数据参考。

番茄斑萎病毒( Tomato spotted wilt virus, TSWV ) 是世界上一种极具危害性的植物病毒，对多种农作物生产造成严重的经济损失。本项目以TSWV NSm蛋白与本氏烟叶绿体蛋白NbTMP14互作为研究基础，进一步解析了两个蛋白互作的分子机制和生物学意义。通过一系列蛋白突变体的构建，分别确定了NbTMP14和NSm蛋白参与互作的重要功能域和位点；TSWV侵染导致NbTMP14与NSm在寄主细胞中的互作位点发生变化；NbTMP14是叶绿体光系统-Ⅰ的组成亚基之一，TSWV侵染下调NbTMP14的表达量并且影响NbTMP14的叶绿体定位，进而阻碍叶绿体正常发育，导致寄主产生病毒症状。上调和下调表达NbTMP14后接种TSWV，检测病毒积累量并观察病毒症状，发现NbTMP14对病毒侵染具有负调控作用。该研究结果有助于全面解析TSWV致病的分子机制，同时也为TSWV病害防治提供了新的分子育种策略。