title: The PEX7-mediated peroxisomal import system is required for fungal development and pathogenicity in Magnaporthe oryzae.
abstract: In eukaryotes, microbodies called peroxisomes play important roles in cellular activities during the life cycle. Previous studies indicate that peroxisomal functions are important for plant infection in many phytopathogenic fungi, but detailed relationships between fungal pathogenicity and peroxisomal function still remain unclear. Here we report the importance of peroxisomal protein import through PTS2 (Peroxisomal Targeting Signal 2) in fungal development and pathogenicity of Magnaporthe oryzae. Using an Agrobacterium tumefaciens-mediated transformation library, a pathogenicity-defective mutant was isolated from M. oryzae and identified as a T-DNA insert in the PTS2 receptor gene, MoPEX7. Gene disruption of MoPEX7 abolished peroxisomal localization of a thiolase (MoTHL1) containing PTS2, supporting its role in the peroxisomal protein import machinery. ΔMopex7 showed significantly reduced mycelial growth on media containing short-chain fatty acids as a sole carbon source. ΔMopex7 produced fewer conidiophores and conidia, but conidial germination was normal. Conidia of ΔMopex7 were able to develop appressoria, but failed to cause disease in plant cells, except after wound inoculation. Appressoria formed by ΔMopex7 showed a defect in turgor generation due to a delay in lipid degradation and increased cell wall porosity during maturation. Taken together, our results suggest that the MoPEX7-mediated peroxisomal matrix protein import system is required for fungal development and pathogenicity M. oryzae.
authors.affiliation: Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Plant Genomics and Breeding Institute, Seoul National University, Seoul, Korea.
authors.forename: Jaeduk
authors.initials: J
authors.lastname: Goh
authors.forename: Junhyun
authors.initials: J
authors.lastname: Jeon
authors.forename: Kyoung Su
authors.initials: KS
authors.lastname: Kim
authors.forename: Jongsun
authors.initials: J
authors.lastname: Park
authors.forename: Sook-Young
authors.initials: SY
authors.lastname: Park
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Lee
mesh_terms: D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D019295:Computational Biology; D005227:Fatty Acids / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018390:Gene Targeting; D005800:Genes, Fungal / Q000235:genetics; D005947:Glucose / Q000494:pharmacology; D008055:Lipids / Q000737:chemistry; D020082:Magnaporthe / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity*; D012275:Oryza / Q000187:drug effects / Q000382:microbiology; D000074437:Peroxisomal Targeting Signal 2 Receptor; D020675:Peroxisomes / Q000187:drug effects / Q000378:metabolism*; D016062:Porosity / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D013172:Spores, Fungal / Q000187:drug effects / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D005656:Fungal Proteins; D008055:Lipids; D000074437:Peroxisomal Targeting Signal 2 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D005947:Glucose