The NLR Protein Encoded by the Resistance Gene Ty-2 Is Triggered by the Replication-Associated Protein Rep/C1 of Tomato Yellow Leaf Curl Virus

作者：Xuexue Shen, Zhe Yan, Xiaoxuan Wang, Yinlei Wang, Marjon Arens, Yongchen Du, Richard G. F. Visser, Richard Kormelink, Yuling Bai, Anne‐Marie A. Wolters · 发表于：Frontiers in Plant Science · 年份：2020 · DOI：10.3389/fpls.2020.545306 · 被引用次数：49 · 研究领域：Plant Virus Research Studies、Insect-Plant Interactions and Control、Plant Parasitism and Resistance

The whitefly-transmitted Tomato yellow leaf curl virus (TYLCV) is one of the most destructive viral pathogens of cultivated tomato. To combat TYLCV, resistance gene Ty-2 has been introduced into cultivated tomato (Solanum lycopersicum) from wild tomato species S. habrochaites by interspecific crossing. Introgression lines with Ty-2 contain a large inversion compared with S. lycopersicum, which causes severe suppression of recombination and has hampered the cloning of Ty-2 so far. Here, we report the fine-mapping and cloning of Ty-2 using ‘intraspecific’ crosses between a Ty-2 introgression line and susceptible S. habrochaites accessions. Ty-2 was shown to encode a nucleotide-binding leucine-rich repeat (NLR) protein. For breeding purposes, a highly specific DNA marker tightly linked to the Ty-2 gene was developed permitting marker-assisted selection. The resistance mediated by Ty-2 was effective against the Israel strain of TYLCV (TYLCV-IL) and Tomato yellow leaf curl virus-[China:Shanghai2] (TYLCV-[CN:SH2]), but not against Tomato yellow leaf curl Sardinia virus (TYLCSV) and leafhopper-transmitted Beet curly top virus (BCTV). By co-infiltration experiments we showed that transient expression of the Rep/C1 protein of TYLCV, but not of TYLCSV triggered a hypersensitive response (HR) in Nicotiana benthamiana plants co-expressing the Ty-2 gene. Our results demonstrate that the Rep/C1 gene of TYLCV-IL is the avirulence determinant of Ty-2-mediated resistance.