查看文章

The potato (Solanum tuberosum) blight pathogen Phytophthora infestans delivers Arg-X-Leu-Arg (RXLR) effector proteins into host cells to subvert plant immune responses and promote colonization. We show that transient expression and stable transgenic expression of the RXLR effector Pi22926 in Nicotiana benthamiana promotes leaf colonization by P. infestans. Pi22926 suppresses cell death triggered by coexpression of the Cladosporium fulvum avirulence protein Avr4 and the tomato (Solanum lycopersicum) resistance protein Cf4. Pi22926 interacts with a potato mitogen-activated protein kinase kinase kinase, StMAP3Kβ2, in the nucleoplasm. Virus-induced gene silencing (VIGS) of the ortholog NbMAP3Kβ2 in N. benthamiana enhances P. infestans colonization and attenuates Cf4/Avr4-induced cell death, indicating that this host protein is a positive regulator of immunity. Cell death induced by Cf4/Avr4 …