Involvement of putative response regulator genes of the rice blast fungus Magnaporthe oryzae in osmotic stress response, fungicide action, and pathogenicity.

Rice blast fungus (Magnaporthe oryzae) has ten histidine kinases (HKs), one histidine-containing phosphotransfer protein (HPt), and three response regulators (RRs) as putative components of the two-component signal transduction system (TCS). Here, we constructed knockout mutants of two putative RR genes (MoSSK1, MoSKN7) and a RR homolog gene (MoRIM15) to analyze the roles of TCS in environmental adaptation and pathogenicity. The DeltaMossk1 strain had increased sensitivity to high osmolarity and decreased sensitivity to fludioxonil.