Hjulsager Charlotte Kristiane, Olsen Birgit Schlichter, Jensen Ditte Marie Kjaer, Cordea Mirela Irina, Krath Britta N, Johansen I Elisabeth, Lund Ole Søgaard
Department of Genetics and Biotechnology, Danish Institute of Agricultural Sciences, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
Virology. 2006 Nov 10;355(1):52-61. doi: 10.1016/j.virol.2006.07.016. Epub 2006 Sep 5.
Viral determinants for overcoming Pisum sativum recessive resistance, sbm-2, against the potyvirus Pea seed-borne mosaic virus (PSbMV) were identified in the region encoding the N-terminal part of the P3 protein. Codons conserved between sbm-2 virulent isolates in this region: Q21, K30 and H122 were found to specifically impair sbm-2 virulence when mutated in selected genetic backgrounds. The corresponding amino acids, Gln21 and Lys30, are neighbored by P3 residues strongly conserved among potyviruses and His122 is conserved particularly in potyviral species infecting legumes. The strongest selective inhibition of sbm-2 virulence, however, was observed by elimination of isolate specific length polymorphisms also located in the N-terminal part of the P3 protein. Length variation in N-terminal P3 is common between potyviral species. However, intra-species length polymorphism in this region was found only among PSbMV isolates. Our findings comply with a model for PSbMV pathotypes having evolved by a diversification of the P3 protein likely to extend to the level of function.
在编码P3蛋白N端部分的区域中，鉴定出了豌豆（Pisum sativum）针对马铃薯Y病毒属豌豆种传花叶病毒（PSbMV）的隐性抗性基因sbm - 2的病毒决定因素。在该区域中，sbm - 2强毒株系之间保守的密码子：Q21、K30和H122，在特定遗传背景下发生突变时，被发现会特异性损害sbm - 2的毒力。相应的氨基酸，Gln21和Lys30，与马铃薯Y病毒属中高度保守的P3残基相邻，而His122尤其在感染豆科植物的马铃薯Y病毒属物种中保守。然而，通过消除同样位于P3蛋白N端部分的分离株特异性长度多态性，观察到了对sbm - 2毒力最强的选择性抑制。P3蛋白N端的长度变异在马铃薯Y病毒属物种之间很常见。然而，仅在PSbMV分离株中发现了该区域的种内长度多态性。我们的研究结果符合一种模型，即PSbMV致病型是通过P3蛋白的多样化进化而来的，这种多样化可能延伸到功能水平。
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