The cucumber mosaic virus (CMV) 2a RNA‐dependent RNA polymerase protein has an additional function in Arabidopsis thaliana, which is to stimulate feeding deterrence (antixenosis) against aphids. Antixenosis is thought to increase the probability that aphids, after acquiring CMV particles from brief probes of an infected plant's epidermal cells, will be discouraged from settling and instead will spread inoculum to neighbouring plants. The amino acid sequences of 2a proteins encoded by a CMV strain that induces antixenosis in A. thaliana (Fny‐CMV) and one that does not (LS‐CMV) were compared to identify residues that might determine the triggering of antixenosis. These data were used to design reassortant viruses comprising Fny‐CMV RNAs 1 and 3, and recombinant CMV RNA 2 molecules encoding chimeric 2a proteins containing sequences derived from LS‐CMV and Fny‐CMV. Antixenosis induction was detected by measuring the mean relative growth rate and fecundity of aphids (Myzus persicae) confined on infected and on mock‐inoculated plants. An amino acid sequence determining antixenosis induction by CMV was found to reside between 2a protein residues 200 and 300. Subsequent mutant analysis delineated this to residue 237. We conjecture that the Fny‐CMV 2a protein valine‐237 plays some role in 2a protein‐induced antixenosis.

中文翻译：

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黄瓜花叶病毒 2a 蛋白对拟南芥蚜虫-植物互作的影响。

黄瓜花叶病毒 (CMV) 2a RNA 依赖性 RNA 聚合酶蛋白在拟南芥中具有额外的功能，即刺激对蚜虫的摄食威慑（抗毒）。抗毒剂被认为会增加蚜虫在从受感染植物表皮细胞的短暂探针中获取 CMV 颗粒后，将被阻止沉降，而是将接种物传播到邻近植物的可能性。在拟南芥中诱导抗排毒的 CMV 菌株编码的 2a 蛋白的氨基酸序列(Fny-CMV) 和没有的 (LS-CMV) 进行比较，以鉴定可能决定触发抗毒作用的残留物。这些数据用于设计包含 Fny-CMV RNA 1 和 3 以及编码嵌合 2a 蛋白的重组 CMV RNA 2 分子的重配病毒，该蛋白包含源自 LS-CMV 和 Fny-CMV 的序列。通过测量限制在感染植物和模拟接种植物上的蚜虫 ( Myzus persicae )的平均相对生长率和繁殖力来检测抗排毒诱导。发现决定 CMV 抗排毒诱导的氨基酸序列位于 2a 蛋白残基 200 和 300 之间。随后的突变分析将其描述为残基 237。我们推测 Fny-CMV 2a 蛋白缬氨酸-237 在 2a 蛋白诱导抗毒素。