Tomato yellow leaf curl virus (TYLCV), a begomovirus, causes large yield losses and breeding for resistance is an effective way to combat this viral disease. The resistance gene Ty‐1 codes for an RNA‐dependent RNA polymerase and has recently been shown to enhance transcriptional gene silencing of TYLCV. Whereas Ty‐1 was earlier shown to also confer resistance to a bipartite begomovirus, here it is shown that Ty‐1 is probably generic to all geminiviruses. A tomato Ty‐1 introgression line, but also stable transformants of susceptible tomato cv. Moneymaker and Nicotiana benthamiana (N. benthamiana) expressing the Ty‐1 gene, exhibited resistance to begomoviruses as well as to the distinct, leafhopper‐transmitted beet curly top virus, a curtovirus. Stable Ty‐1 transformants of N. benthamiana and tomato showed fewer symptoms and reduced viral titres on infection compared to wild‐type plants. TYLCV infections in wild‐type N. benthamiana plants in the additional presence of a betasatellite led to increased symptom severity and a consistent, slightly lowered virus titre relative to the high averaged levels seen in the absence of the betasatellite. On the contrary, in Ty‐1 transformed N. benthamiana viral titres increased in the presence of the betasatellite. The same was observed when these Ty‐1‐encoding plants were challenged with TYLCV and a potato virus X construct expressing the RNA interference suppressor protein βC1 encoded by the betasatellite. The resistance spectrum of Ty‐1 and the durability of the resistance are discussed in light of antiviral RNA interference and viral counter defence strategies.

中文翻译：

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Ty-1，一种针对双生病毒的通用抗性基因，因 β 卫星的共同复制而受到损害。


番茄黄曲叶病毒（TYLCV）是一种番茄病毒，会造成大量产量损失，抗性育种是对抗这种病毒性疾病的有效方法。抗性基因Ty-1编码一种依赖于 RNA 的 RNA 聚合酶，最近被证明可以增强 TYLCV 的转录基因沉默。虽然Ty-1之前被证明也具有对二分贝戈莫病毒的抗性，但这里表明Ty-1可能对所有双生病毒都是通用的。番茄Ty-1基因渗入系，也是易感番茄品种的稳定转化体。表达Ty-1基因的 Moneymaker 和本塞姆氏烟草（N.benthamiana）表现出对 Begomoviruses 以及独特的叶蝉传播的甜菜卷顶病毒（一种 Curtovirus）的抗性。与野生型植物相比，本塞姆氏烟草和番茄的稳定Ty-1转化体在感染时表现出较少的症状和较低的病毒滴度。在额外存在 β 卫星的情况下，野生型本塞姆氏烟草植物中的 TYLCV 感染导致症状严重程度增加，并且相对于不存在 β 卫星时观察到的高平均水平，病毒滴度一致且略有降低。相反，在Ty-1转化的本塞姆氏烟草中，在存在 β 卫星的情况下，病毒滴度增加。当这些编码Ty-1 的植物受到 TYLCV 和表达由 β 卫星编码的 RNA 干扰抑制蛋白 βC1 的马铃薯病毒 X 构建体攻击时，观察到了同样的情况。从抗病毒RNA干扰和病毒反防御策略的角度讨论了Ty-1的耐药谱和耐药性的持久性。