Sato Masanao, Masuta Chikara, Uyeda Ichiro
Pathogen-Plant Interactions Group, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
Mol Plant Microbe Interact. 2003 Nov;16(11):994-1002. doi: 10.1094/MPMI.2003.16.11.994.
We characterized the resistance of the common bean cv. Jolanda to Clover yellow vein virus no. 30 (ClYVV). After inoculation, the virus was detected in neither inoculated nor upper leaves, suggesting that the resistance operates at either the viral replication or cell-to-cell movement level. To analyze the mechanism of resistance, we developed a green fluorescent protein (GFP)-tagged ClYVV, and monitored GFP fluorescence at sites of infection on ClYVV-inoculated leaves. No GFP fluorescence was detected in Jolanda, whereas its expression in single cells and spread on inoculated leaves were observed clearly in susceptible cultivars. ClYVV-introduced Jolanda cells were found to be still viable; therefore, it is unlikely that the restriction of multiplication was due to rapid cell death. Genetic analysis indicated that a single recessive locus controlled the resistant phenotype of Jolanda. We designated this locus desc (determinant of susceptibility to ClYVV). Meanwhile, a spontaneous mutant virus that overcomes the resistance (ClYVV-Br) was isolated. Inoculation assays using chimeric viruses suggested that a viral genome-linked protein (VPg) might be the avirulence determinant. The resistance mechanism may be associated with the role of VPg in the viral infection cycle.
我们对菜豆品种乔兰达（Jolanda）对三叶草黄脉病毒30号（ClYVV）的抗性进行了表征。接种后，在接种叶和上部叶中均未检测到该病毒，这表明抗性作用于病毒复制或细胞间移动水平。为了分析抗性机制，我们构建了绿色荧光蛋白（GFP）标记的ClYVV，并监测了接种ClYVV叶片上感染部位的GFP荧光。在乔兰达中未检测到GFP荧光，而在感病品种中则清晰地观察到其在单个细胞中的表达及在接种叶片上的扩散。发现导入ClYVV的乔兰达细胞仍然存活；因此，繁殖受限不太可能是由于细胞快速死亡所致。遗传分析表明，一个单隐性位点控制着乔兰达的抗性表型。我们将该位点命名为desc（对ClYVV易感性的决定因素）。同时，分离出一种克服该抗性的自发突变病毒（ClYVV-Br）。使用嵌合病毒的接种试验表明，病毒基因组连接蛋白（VPg）可能是无毒决定因素。抗性机制可能与VPg在病毒感染周期中的作用有关。
