Colletotrichum orbiculare FAM1 Encodes a Novel Woronin Body-Associated Pex22 Peroxin Required for Appressorium-Mediated Plant Infection

摘要: ABSTRACT The cucumber anthracnose fungus Colletotrichum orbiculare forms specialized cells called appressoria for host penetration. We identified a gene, FAM1 , encoding novel peroxin protein that is essential peroxisome biogenesis and associates with Woronin bodies (WBs), dense-core vesicles found only in filamentous ascomycete fungi which function to maintain cellular integrity. fam1 disrupted mutants were unable grow on medium containing oleic acids as the sole carbon source nonpathogenic, being defective both appressorium melanization Fluorescent proteins carrying peroxisomal targeting signals (PTSs) not imported into peroxisomes of mutants, suggesting gene (peroxin). did show significant homology any Saccharomyces cerevisiae peroxins but resembled conserved ascomycete-specific Pex22-like contain predicted Pex4-binding site are potentially involved recycling PTS receptors from cytosol. C. orbiculare complemented matrix import defect S. pex22 mutant. Confocal microscopy Fam1-GFP (green fluorescent protein) fusion immunoelectron anti-Fam1 antibodies showed Fam1 localized nascent WBs budding mature WBs. Association was confirmed by colocalization WB CoHex1 ( Hex1) membrane CoWsc Wsc) subcellular fractionation Western blotting CoHex1. In WB-deficient cohex1 redirected membrane. Our results WB-associated required pathogenesis raise possibility receptor occurs IMPORTANCE causing damaging disease Cucurbitaceae plants. this paper, we characterize pathogen . Although no genes present cerevisiae, contains typical Pex22 proteins, complements completely function, fatty acid metabolism, pathogenicity. Remarkably, specifically bounding bodies, small peroxisome-derived organelles unique septal pore plugging. finding suggests these have coopted body during import.