Identification of Natural Resistance Mediated by Recognition of Phytophthora infestans Effector Gene Avr3aEM in Potato. uri icon

abstract

  • Late blight is considered the most renowned devastating potato disease worldwide. Resistance gene (R)-based resistance to late blight is the most effective method to inhibit infection by the causal agentPhytophthora infestans. However, the limited availability of resistant potato varieties and the rapid loss ofRresistance, caused byP. infestansvirulence variability, make disease control rely on fungicide application. We employed anAgrobacterium tumefaciens-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 inPiAvr3a(EM), the most common virulent allele ofPiAvr3a(KI)that triggers aR3a-mediated hypersensitive response (HR) and late blight resistance. Through our significantly improvedA. tumefaciens-mediated transient gene expression assay in potato using cultured seedlings, we characterized two dominant potato varieties, Qingshu9 and Longshu7, in China by transient expression ofP. infestanseffector genes. Transient expression of 10 known avirulence genes showed thatPiAvr4andPiAvr8 (PiAvrsmira2)could induce HR in Qingshu9, andPiAvrvnt1.1in Longshu7, respectively. Our study also indicated thatPiAvr3a(EM)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 byPiAvr3a(EM)recognition in Qingshu9 and Longshu7 will facilitate breeding for improved potato resistance againstP. infestans.

publication date

  • 2020
  • 2020