Functional Analysis of Lipid Metabolism in Magnaporthe grisea Reveals a Requirement for Peroxisomal Fatty Acid beta-Oxidation During Appressorium-Mediated Plant Infection

• Published in: Molecular plant-microbe interactions Vol. 20; no. 5; pp. 475 - 491
• Main Authors: Wang, Z.Y, Soanes, D.M, Kershaw, M.J, Talbot, N.J
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.05.2007; The American Phytopathological Society
• Subjects: apoptosis; appressoria; Biological and medical sciences; Cell Wall - metabolism; Cell Wall - ultrastructure; conidia; disease course; enzyme activity; epidermis (plant); Fatty Acids - metabolism; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Fungal plant pathogens; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Expression Regulation, Fungal; Genome, Fungal; genomics; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Lipase - genetics; Lipase - metabolism; lipid metabolism; Lipid Metabolism - physiology; lipid peroxidation; Magnaporthe - genetics; Magnaporthe - growth & development; Magnaporthe - metabolism; Magnaporthe grisea; microbial colonization; microbial genetics; Microscopy, Electron; Microscopy, Fluorescence; molecular sequence data; Mutation; nucleotide sequences; Onions - microbiology; Oryza - microbiology; Oxidation-Reduction; peroxisomes; Peroxisomes - enzymology; Peroxisomes - metabolism; Phytopathology. Animal pests. Plant and forest protection; plant cuticle; Plant Diseases - microbiology; plant pathogenic fungi; Plants - microbiology; sequence analysis; triacylglycerol lipase; turgor; virulence; Monocotyledones; Plant pathogen; Triacylglycerol lipase; Lipids; Esterases; Identification; Cereal crop; Fungi; Oryza sativa; Gene; Gramineae; Angiospermae; Deletion; Ascomycetes; Oxidation; Thallophyta; Nucleotide sequence; Enzyme; Metabolism; Fatty acids; Lipolysis; Carboxylic ester hydrolases; Magnaporthe grisea; virulence; Cell death; β Oxidation; Hydrolases; Spermatophyta; Intracellular; Mutation
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-20-5-0475

The rice blast fungus Magnaporthe grisea infects plants by means of specialized infection structures known as appressoria. Turgor generated in the appressorium provides the invasive force that allows the fungus to breach the leaf cuticle with a narrow-penetration hypha gaining entry to the underlying epidermal cell. Appressorium maturation in M. grisea involves mass transfer of lipid bodies to the developing appressorium, coupled to autophagic cell death in the conidium and rapid lipolysis at the onset of appressorial turgor generation. Here, we report identification of the principal components of lipid metabolism in M. grisea based on genome sequence analysis. We show that deletion of any of the eight putative intracellular triacylglycerol lipase-encoding genes from the fungus is insufficient to prevent plant infection, highlighting the complexity and redundancy associated with appressorial lipolysis. In contrast, we demonstrate that a peroxisomally located multifunctional, fatty acid beta-oxidation enzyme is critical to appressorium physiology, and blocking peroxisomal biogenesis prevents plant infection. Taken together, our results indicate that, although triacylglycerol breakdown in the appressorium involves the concerted action of several lipases, fatty acid metabolism and consequent generation of acetyl CoA are necessary for M. grisea to complete its prepenetration phase of development and enter the host plant.