A member of the glycoside hydrolase family 76 is involved in growth, conidiation, and virulence in rice blast fungus

Abstract

Glycoside hydrolase family 76 (GH76) proteins with their endo-α-1,6-mannanases domains are required for cell wall biogenesis in several model fungi, including Saccharomyces cerevisiae, Candida albicans, and Neurospora crassa. However, biological roles of GH76 proteins in phytopathogenic fungi remain unknown. The genome of the rice blast fungus Pyricularia oryzae contains seven GH76 protein-encoding genes. In this study, we functionally characterized one of them, PoGH76-1, which is highly expressed in conidia. The deletion of PoGH76-1 led to severe defects in colony growth and conidiation. Conidia produced by the PoGH76-1 knockout mutant were mostly one- and two-celled. Deletion of PoGH76-1 also resulted in impaired appressorium maturation, appressorial penetration, and attenuated virulence on rice leaves. Taken together, our findings suggest that PoGH76-1 functions as an important determinant of fungal growth, development, and virulence in P. oryzae.