One of Three Pex11 Family Members Is Required for Peroxisomal Proliferation and Full Virulence of the Rice Blast Fungus Magnaporthe oryzae.

Peroxisomes play important roles in metabolisms of eukaryotes and infection of plant fungal pathogens. These organelles proliferate by de novo formation or division in response to environmental stimulation. Although the assembly of peroxisomes was documented in fungal pathogens, their division and its relationship to pathogenicity remain obscure. In present work, we analyzed the roles of three Pex11 family members in peroxisomal division and pathogenicity of the rice blast fungus Magnaporthe oryzae. Deletion of MoPEX11A led to fewer but enlarged peroxisomes, and impaired the separation of Woronin bodies from peroxisomes, while deletion of MoPEX11B or MoPEX11C put no evident impacts to peroxisomal profiles. MoPEX11A mutant exhibited typical peroxisome related defects, delayed conidial germination and appressoria formation, and decreased appressorial turgor and host penetration. As a result, the virulence of MoPEX11A mutant was greatly reduced. Deletion of MoPEX11B and MoPEX11C did not alter the virulence of the fungus. Further, double or triple deletions of the three genes were unable to enhance the virulence decrease in MoPEX11A mutant. Our data indicated that MoPEX11A is the main factor modulating peroxisomal division and is required for full virulence of the fungus.