Identification of Natural Resistance Mediated by Recognition of Effector Gene in Potato.

Late blight is considered the most renowned devastating potato disease worldwide. Resistance gene ()-based resistance to late blight is the most effective method to inhibit infection by the causal agent . However, the limited availability of resistant potato varieties and the rapid loss of resistance, caused by virulence variability, make disease control rely on fungicide application. We employed an -mediated transient gene expression assay and effector biology approach to understand late blight resistance of Chinese varieties that showed years of promising field performance. We are particularly interested in , the most common virulent allele of that triggers a -mediated hypersensitive response (HR) and late blight resistance. Through our significantly improved -mediated transient gene expression assay in potato using cultured seedlings, we characterized two dominant potato varieties, Qingshu9 and Longshu7, in China by transient expression of effector genes. Transient expression of 10 known avirulence genes showed that and could induce HR in Qingshu9, and in Longshu7, respectively. Our study also indicated that is recognized by these two potato varieties, and is likely involved in their significant field performance of late blight resistance. The identification of natural resistance mediated by recognition in Qingshu9 and Longshu7 will facilitate breeding for improved potato resistance against .