Role of lipid catabolism in the pathogenicity of rice-blast fungus Magnaporthe grisea

Abstract

The cereal pathogen Magnaporthe grisea is a model system for studying fungal pathogenesis. For host invasion, Magnaporthe develops a melanized infection cell called the appressorium which utilizes hydrostatic turgor pressure to force a penetration peg through the host cuticle. It has been proposed that lipid degradation and auxiliary pathways produce essential metabolites necessary for pathogenesis. Knowledge about the specific contributions and the subcellular compartmentalization of the lipid oxidation pathways is crucial for a better understanding of metabolism associated with fungal pathogenesis. This study reports the detailed analysis and essential functions of the metabolic processes associated with peroxisomes and mitochondria during Magnaporthe pathogenesis. Functional characterization of Peroxin 6, Carnitine acetyltransferase, Multifunctional enzyme and Enoyl-CoA hydratase, reported herein, showed that peroxisomal lipid catabolism is essential for generating appressorial melanin and for cell wall assembly during host penetration. Whereas mitochondrial beta-oxidation function is required for vegetative growth, conidiogenesis and for proliferation within the host.