Isolation of a resistance gene against potato virus Y from Solanacearum plants

据报道，烟草栽培品种VAM具有隐性马铃薯Y病毒抗性基因nu α。用日本马铃薯Y病毒（PVY）分离物接种VAM植株，观察到不同程度的抗性。VAM品种是高抗大多数PVY菌株测试和耐受三个坏死株PVY-T分离株。根据从组织打印和印刷机印迹获得的数据，阻力似乎主要是在细胞间运动的水平。PVY在VAM原生质体中复制，但复制比感病烟草低30%，表明复制受损也有助于抗性。为了鉴定参与VAM抗性的病毒基因产物，我们通过将脉带（0株）分离物多次通过VAM植物来分离自发抗性破坏突变体。通过比较突变体及其原始分离物的氨基酸序列，我们确定了与VAM抗性破坏相关的VPg结构域中的单个氨基酸取代。总之，这些结果表明，除了其在复制中的作用，VPg在PVY的细胞间运动中起着重要作用。

Tobacco cultivar VAM is reported to have the recessive potyvirus resistance gene nu alpha. Varied levels of resistance were observed in VAM plants inoculated with Japanese potato virus Y (PVY) isolates. The VAM cultivar was highly resistant to most of the PVY isolates tested and tolerant to three necrotic strain isolates of PVY-T.Based on data obtained from tissue printing and press blotting, the resistance appeared to be mainly at the level of cell-to-cell movement. PVY replicated in VAM protoplasts, but the replication was 30% lower than in susceptible tobacco, suggesting that impairment of replication also contributes to resistance. To identify the viral gene product(s) involved in VAM resistance, we isolated spontaneous resistance-breaking mutants by passing vein-banding (0 strain) isolates several times through VAM plants. By comparing the amino acid sequences of the mutants and their original isolates, we identified a single amino acid substitution in the VPg domain that is correlated with VAM resistance breaking. Together, these results suggest that, in addition to its role in replication, VPg plays an important role in the cell-to-cell movement of PVY.