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

据报道，烟草品种VAM具有隐性抗痘病毒基因nu α。在接种日本马铃薯Y病毒（PVY）分离株的VAM植株上观察到不同程度的抗性。VAM品种对大多数PVY菌株具有高度抗性，对PVY- t的3个坏死菌株具有耐受性。根据从组织印刷和压印迹获得的数据，阻力似乎主要在细胞间运动水平。PVY在VAM原生质体中复制，但复制率比易感烟草低30%，表明复制受损也有助于抗性。为了鉴定与VAM抗性相关的病毒基因产物，我们通过多次通过VAM植物传递静脉带（0株）分离物，分离出自发破药突变体。通过比较突变体及其原始分离株的氨基酸序列，我们在VPg结构域中发现了一个与VAM抗性断裂相关的单氨基酸替代。综上所述，这些结果表明，除了在复制中发挥作用外，VPg在PVY的细胞间运动中也起着重要作用。

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.