Identification and Functional Analysis of the Gene Conferring Resistance to Late Blight () in Tomato.

Late blight is a destructive disease affecting tomato production. The identification and characterization of resistance (R) genes are critical for the breeding of late blight-resistant cultivars. The incompletely dominant gene confers resistance against the race T of in tomatoes. Herein, we identified () as a candidate gene for through the analysis of sequences and post-inoculation expression levels of genes located within the fine mapping interval. The was subsequently validated to be a gene through targeted knockout and complementation analyses. It encodes a CC-NBS-LRR disease resistance protein, and transient expression assays conducted in the leaves of indicate that is predominantly localized within the nucleus. In comparison to its susceptible allele (), the transient expression of can elicit hypersensitive responses (HR) in , and subsequent investigations indicate that the structural integrity of the protein is likely a requirement for inducing HR in this species. Furthermore, ethylene and salicylic acid hormonal signaling pathways may mediate the transmission of the resistance signal, with - and HR-related genes potentially involved in the -mediated resistance. Our results could provide a theoretical foundation for the molecular breeding of tomato varieties resistant to late blight and offer valuable insights into elucidating the interaction mechanism between tomatoes and .