衣壳蛋白参与调控马铃薯Y病毒在珊西烟上症状的关键氨基酸鉴定  

Determination of critical amino acids in potato virus Y coat protein involved in the formation of vein necrosis symptom in Nicotiana tabacum cv.Xanthi plants

作　　者：姬丽云 赵平祥 闫志勇 耿超[1] 田延平[1] 李向东[1] 王凤龙[2] JI Liyun;ZHAO Pingxiang;YAN Zhiyong;GENG Chao;TIAN Yanping;LI Xiangdong;WANG Fenglong(Department of Plant Pathology,College of Plant Protection,Shandong Agricultural University,Tai'an 271018,China;Tobacco Research Institute of Chinese Academy of Agricultural Sciences,Qingdao,276101,China)

机构地区：[1]山东农业大学植物保护学院植物病理学系,泰安271018 [2]中国农业科学院烟草研究所,青岛276101

出　　处：《植物病理学报》2023年第5期870-880,共11页Acta Phytopathologica Sinica

基　　金：国家自然科学基金(31720103912,32072387);山东省烟草公司(KN275)。

摘　　要：马铃薯Y病毒(potato virus Y, PVY)可侵染马铃薯和烟草等多种作物,造成严重的经济损失。衣壳蛋白(coat protein, CP)与辅助成分-蛋白酶(helper component proteinase, HC-Pro)互作调控PVY的蚜虫传播,但是否参与PVY在珊西烟上叶脉坏死症状的形成还不清楚。本研究分析了前期获得的84个PVY CP突变体在珊西烟上的症状,发现突变体PVY-71和PVY-82不能引起叶脉坏死症状。将CP中保守氨基酸天冬氨酸(D6)和甘氨酸(G9)的密码子分别突变为天冬酰胺(N)和精氨酸(R)的密码子,对应突变体分别命名为pCamPVY-CP^(D6N)和pCamPVY-CP^(G9R),接种珊西烟10 d后,两个突变体均能系统侵染珊西烟,CP积累水平与野生型PVYN605相似,但均不引起叶脉坏死症状。萤火素酶互补试验结果发现,与野生型CP相比,CP突变体与HC-Pro的互作强度减弱。本研究首次为CP参与调控PVY引起的叶脉坏死症状提供了遗传学证据,其D6和G9为关键氨基酸。研究结果对明确CP在PVY侵染过程中的作用,解析PVY坏死症状形成机制具有重要意义。Potato virus Y(PVY)can infect many crops including potato and tobacco,and cause huge economic losses.PVY-encoded coat protein(CP)interacts with helper component proteinase(HC-Pro)to regulate the aphid transmission of PVY.However,its role in the formation of PVY vein necrosis symptoms is unclear.Here,we analyzed the symptoms of 84 PVY CP mutants on Nicotiana tabacum cv.Xanthi plants and found two mutants,PVY-71 and PVY-82,which have lost their ability to induce vein necrosis in N.tabacum cv.Xanthi plants.Site-directed mutagenesis was carried out to identify the critical amino acids in CP in the formation of vein necrosis on N.tabacum cv.Xanthi plants.Two mutants,namely pCamPVY-CP^(D6N)and pCamPVY-CP^(G9R),in which the codons for the sixth amino acid,Aspartic acid(D6),and the ninth amino acid,Glycine(G9),of CP were mutated to those for asparagine(N)and arginine(R),respectively,were obtained.Both mutants can infect N.tabacum cv.Xanthi plants systemically and have similar virus accumulation levels to wild-type PVY~N605.However,they could not induce vein necrosis in N.tabacum cv.Xanthi plants.Luciferase complementation assay showed that the interaction strength between mutant CP and HC-Pro was also reduced.It is the first report that PVY CP is one of the vein necrosis determinants on N.tabacum cv.Xanthi plants,and the conserved amino acids D~6 and G~9 played an essential role during this process.These findings will help us to understand the role of CP in the PVY vein necrosis symptom formation in N.tabacum cv.Xanthi plants and the role of CP in PVY infection.

关 键 词：马铃薯Y病毒 衣壳蛋白 叶脉坏死 定点突变 辅助成分-蛋白酶 

分 类 号：S432.41[农业科学—植物病理学]