Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM), Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Estación Experimental "La Mayora", E-29750 Algarrobo-Costa, Málaga, Spain.
Phytopathology. 2023 Jul;113(7):1347-1359. doi: 10.1094/PHYTO-09-22-0334-R. Epub 2023 Aug 29.
Tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato crops in warm regions of the world, and is associated with infections of several whitefly ()-transmitted single-stranded (ss)DNA begomoviruses (genus , family ). The most widespread begomovirus isolates associated with TYLCD are those of the type strain of the species, known as Israel (TYLCV-IL). The gene is widely used in commercial tomato cultivars to control TYLCV-IL damage, providing resistance to the virus by restricting viral accumulation and tolerance to TYLCD by inhibiting disease symptoms. However, several reports suggest that TYLCV-IL-like isolates are adapting to the gene and are causes of concern for possibly overcoming the provided control. This is the case with TYLCV-IL IS76-like recombinants that have a small genome fragment acquired by genetic exchange from an isolate of , another begomovirus species associated with TYLCD. Here we show that TYLCV-IL IS76-like isolates partially break down the TYLCD-tolerance provided by the gene and that virulence differences might exist between isolates. Interestingly, we demonstrate that mixed infections with an isolate of the crinivirus (genus , family ) species (ToCV), an ssRNA virus also transmitted by and emerging worldwide in tomato crops, boosts the breakdown of the TYLCD-tolerance provided by the gene either with TYLCV-IL IS76-like or canonical TYLCV-IL isolates. Moreover, we demonstrate the incorporation of the gene in -commercial tomatoes to restrict (no virus or virus traces, no symptoms) systemic infections of recombinant TYLCV-IL IS76-like and canonical TYLCV-IL isolates, even in the presence of ToCV infections, which provides more robust and durable control of TYLCD.
番茄黄曲叶病毒病（TYLCD）对世界温暖地区的番茄作物造成严重损害，与几种粉虱（）传播的单链（ss）DNA 伴随病毒（属，家族）的感染有关。与 TYLCD 相关的最广泛的伴随病毒分离株是以色列（TYLCV-IL）种的典型菌株。基因广泛用于商业番茄品种中，以控制 TYLCV-IL 损伤，通过限制病毒积累和通过抑制病症来耐受 TYLCD 来提供对病毒的抗性。然而，有几项报告表明，TYLCV-IL 样分离株正在适应基因，并且可能克服所提供的控制措施而引起关注。TYLCV-IL IS76 样重组体就是这种情况，它从另一种与 TYLCD 相关的伴随病毒种获得了一个小的基因组片段，通过遗传交换获得。在这里，我们表明 TYLCV-IL IS76 样分离株部分破坏了由基因提供的 TYLCD 耐受性，并且分离株之间可能存在毒力差异。有趣的是，我们证明了与 crinivirus（属，家族）种 （ToCV）的混合感染，一种由粉虱传播的 ssRNA 病毒，并且在番茄作物中在全世界范围内出现，会破坏由基因提供的 TYLCD 耐受性，无论是 TYLCV-IL IS76 样还是典型的 TYLCV-IL 分离株。此外，我们证明了将基因整合到商业番茄中，可以限制（无病毒或病毒痕迹，无症状）重组 TYLCV-IL IS76 样和典型 TYLCV-IL 分离株的系统性感染，即使存在 ToCV 感染，这也为 TYLCD 提供了更强大和持久的控制。
