Multiple Coat Protein Mutations Abolish Recognition of Pepino mosaic potexvirus (PepMV) by the Potato Rx Resistance Gene in Transgenic Tomatoes
Multiple Coat Protein Mutations Abolish Recognition of Pepino mosaic potexvirus (PepMV) by the Potato Rx Resistance Gene in Transgenic Tomatoes
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DOI：
10.1094/mpmi-23-4-0376
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发表时间：
2010-04-01
影响因子：
3.5
通讯作者：
Bendahmane, Abdelhafid
中科院分区：
文献类型：
--
作者：
Candresse, Thierry;Marais, Armelle;Bendahmane, Abdelhafid
尽管Pepino花叶病毒（PepMV）和马铃薯X病毒（PVX）在它们的外壳蛋白（CP）中共享不到40%的同一性，但是Rx的已知PVX激发子、转基因番茄（cv.然而，在低百分比的植物中，观察到PepMV积累，并且回接种实验证明这些植物含有破坏抗性的PepMV变体。这些变体的CP基因的测序显示在CP的氨基酸41至125区域中积累突变，而在未进化的分离株中没有观察到突变。农杆菌渗透介导的突变体CP的瞬时表达表明，他们有一个大大减弱或废除的能力，诱导在Rx表达烟草本塞姆氏叶过敏反应。截短形式的PepMV CP的瞬时表达允许鉴定最小的激发子结构域（氨基酸30至136）。这些结果表明，基于Rx的传感系统能够识别PepMV CP，但与PVX的情况相反，PVX仅已知两个紧密间隔的耐药性破坏突变，PepMV CP的显著延伸上的许多突变允许逃避Rx的识别。
Despite the fact that Pepino mosaic virus (PepMV) and Potato virus X (PVX) share less than 40% identity in their coat proteins (CP), the known PVX elicitor of Rx, transgenic tomato (cv. Microtom) plants expressing a functional potato Rx resistance gene showed resistance toward PepMV However, in a low percentage of plants, PepMV accumulation was observed and back inoculation experiments demonstrated that these plants contained resistance-breaking PepMV variants. Sequencing of the CP gene of these variants showed the accumulation of mutations in the amino acid 41 to 125 region the CP, whereas no mutations were observed in the nonevolved isolates. Agroinfiltration-mediated transient expression of the mutant CP demonstrated that they had a greatly attenuated or abolished ability to induce a hypersensitive reaction in Rx-expressing Nicotiana benthamiana leaves. The transient expression of truncated forms of the PepMV CP allowed the identification of a minimal elicitor domain (amino acids 30 to 136). These results demonstrate that the Rx-based sensing system is able to recognize the PepMV CP but, contrary to the situation with PVX, for which only two closely spaced resistance-breaking mutations are known, many mutations over a significant stretch of the PepMV CP allow escape from recognition by Rx.