Natural variation and functional analyses provide evidence for co-evolution between plant eIF4E and potyviral VPg
Natural variation and functional analyses provide evidence for co-evolution between plant eIF4E and potyviral VPg
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DOI：
10.1111/j.1365-313x.2008.03407.x
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发表时间：
2008-04-01
期刊：
影响因子：
7.2
通讯作者：
Caranta, Carole
中科院分区：
文献类型：
--
作者：
Charron, Carine;Nicolai, Maryse;Caranta, Carole
真核生物翻译起始因子4E（eIF4E）中的氨基酸取代导致包括辣椒属（Capsicum spp.）在内的一系列植物物种对马铃薯Y病毒属的隐性抗性。相应地，病毒基因组连接蛋白（VPg）中心部分的氨基酸变化负责马铃薯Y病毒克服eIF4E介导的抗性的能力。一个关键的观察结果是，eIF4E和VPg之间的物理相互作用是病毒感染所必需的，而导致耐药性的eIF4E突变会阻止VPg结合并抑制病毒周期。本研究对全球25个C. annuum登记鉴定了10个等位基因变体，其具有聚集在eIF4E的两个表面环中的专门的非同义变异。抗性和遗传互补分析表明，pvr2变异体，每个签名氨基酸的变化，对应马铃薯Y病毒抗性等位基因。系统分析了10个pvr2等位基因编码的eIF4E蛋白与毒力和无毒力马铃薯Y病毒（PVY）和烟草蚀纹病毒（TEV）株系VPg之间的相互作用，结果表明，抗性表型源于eIF4E和VPg之间相互作用的破坏，病毒对eIF4E介导的抗性的适应源于与抗性蛋白的恢复相互作用。通过C. annuum eIF4E蛋白进一步表明氨基酸变化不妨碍必需的eIF4E功能。总之，这些结果支持辣椒eIF4E和马铃薯Y病毒VPg之间的共同进化“军备竞赛”。
Amino acid substitutions in the eukaryotic translation initiation factor 4E (eIF4E) result in recessive resistance to potyviruses in a range of plant species, including Capsicum spp. Correspondingly, amino acid changes in the central part of the viral genome-linked protein (VPg) are responsible for the potyvirus's ability to overcome eIF4E-mediated resistance. A key observation was that physical interaction between eIF4E and the VPg is required for viral infection, and eIF4E mutations that cause resistance prevent VPg binding and inhibit the viral cycle. In this study, polymorphism analysis of the pvr2-eIF4E coding sequence in a worldwide sample of 25 C. annuum accessions identified 10 allelic variants with exclusively non-synonymous variations clustered in two surface loops of eIF4E. Resistance and genetic complementation assays demonstrated that pvr2 variants, each with signature amino acid changes, corresponded to potyvirus resistance alleles. Systematic analysis of the interactions between eIF4E proteins encoded by the 10 pvr2 alleles and VPgs of virulent and avirulent potato virus Y (PVY) and tobacco etch virus (TEV) strains demonstrated that resistance phenotypes arose from disruption of the interaction between eIF4E and VPg, and that viral adaptation to eIF4E-mediated resistance resulted from restored interaction with the resistance protein. Complementation of an eIF4E knockout yeast strain by C. annuum eIF4E proteins further shows that amino acid changes did not impede essential eIF4E functions. Altogether, these results argue in favour of a co-evolutionary 'arms race' between Capsicum eIF4E and potyviral VPg.