Pex13 and Pex14, the key components of the peroxisomal docking complex, are required for peroxisome formation, host infection and pathogenicity-related morphogenesis in Magnaporthe oryzae.

Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfill multiple important types of metabolism. Pex13 and Pex14 are two key components of the peroxisomal docking complex that play crucial roles in the import of peroxisomal matrix proteins into peroxisomes in yeasts and mammals. In the present work, we investigated the roles of the homologues of Pex13 and Pex14 (Mopex13 and Mopex14) in the rice blast fungus Magnaporthe oryzae. Mopex13 and Mopex14 were distributed on the peroxisomal membrane and were both essential for the maintenance of Mopex14/17 on the peroxisomal membrane. Mopex13 and Mopex14 interacted with each other and with Mopex14/17 and peroxisomal matrix proteins receptors. Disruption of Mopex13 and Mopex14 resulted in a cytoplasmic distribution of peroxisomal matrix proteins and the Woronin body protein Hex1 but did not alter the distribution of peroxisomal membrane proteins. In Δmopex13 and Δmopex14 cells, peroxisomes were detected on fewer occasions in the ultrastructure analysis; moreover, the Woronin bodies and related structures were dramatically affected. The Δmopex13 and Δmopex14 mutants showed reduced vegetative growth, conidial generation and mycelial melanization, and they were both nonpathogenic to their hosts. Δmopex13 showed reduced conidial germination, appressorial formation and appressorial morphology, and both Δmopex13 and Δmopex14 exhibited deficiencies in appressorial turgor generation. The infection failures in Δmopex13 and Δmopex14 were also due to their reduced ability to degrade fatty acids and to endure reactive oxygen species and cell wall-disrupting compounds, as the artificial offset of these factors partially recovered the pathogenicity of the mutants. Additionally, we found that Mopex13 and Mopex14 were required for the sexual reproduction of the fungus. These data indicate that Mopex13 and Mopex14, as key component of the peroxisomal docking complex in the rice blast fungus, are indispensable for peroxisomal biogenesis, fungal development and pathogenicity.