Potassium (K⁺) is required by plants for growth and development, and also contributes to immunity against pathogens. However, it has not been established whether pathogens modulate host K⁺ signaling pathways to enhance virulence and subvert host immunity.

The hemibiotrophic fungus, Magnaporthe oryzae, causes rice blast disease in all rice-growing countries and also causes wheat blast in South America and Bangladesh. Recently, researchers at State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection of Chinese Academy of Agricultural Sciences (CAAS) published a research paper on PLOS Pathogens about the mechanism that the effector protein AvrPiz-t from the rice blast pathogen M. oryzae targets a K⁺ channel to subvert plant immunity.

AvrPiz-t interacts with the rice plasma-membrane-localized K⁺ channel protein OsAKT1 and specifically suppresses the OsAKT1-mediated K⁺ currents. Genetic and phenotypic analyses show that loss of OsAKT1 leads to decreased K⁺ content and reduced resistance against M. oryzae. Strikingly, AvrPiz-t interferes with the association of OsAKT1 with its upstream regulator, the cytoplasmic kinase OsCIPK23, which also plays a positive role in K⁺ absorption and resistance to M. oryzae. Furthermore, this study shows a direct correlation between blast disease resistance and external K⁺ status in rice plants. Together, these results present a novel mechanism by which a pathogen suppresses plant host immunity by modulating a host K⁺ channel. More details are available on the bellow links:

http://journals.plos.org/plospathogens/article?id="10.1371/journal.ppat.1006878