The Function Analysis Of Mopex33,Mopex23 And Mopex24 In Magnaporthe Oryzae

Magnaporthe oryzae is an ascomycotina filamentous fungus, which leads to the destructive diseases on rice, rice blast and also a model fungus representing plant pathogenic fungi. The investigation on pathogenesis of M. oryzae is thus important for the study of plant pathology.Peroxisomes are one type of important organelles in eukaryotic organisms which contribute to several crucial metabolic processes such as β-oxidation of fatty acids, biosynthesis of ether phospholipids and metabolism of reactive oxygen species. Peroxisomes are highly dynamic organelles that rapidly assemble, multiply and degrade in response to metabolic needs. In recent years, the peroxisomal metabolisms were found indispensable in the infection of plant fungal pathogens.Peroxisome assembly, division and inheritance are controlled by at least 32 proteins termed peroxins that are encoded by the PEX genes. During the assembly of the organelles, the peroxisomal matrix proteins are recognized and translocated by the receptors, Pex5p and Pex7p, to the peroxisomal membrane, where a protein complex called docking complex mediates the subsequent import. The docking complex is composed of Pex13p and Pex14p, and in yeast species, possess an additional component, Pex17p. By genome analysis, Pexl3p and Pexl4p could be found in M. oryzae. However, Pex17p are absent in of M. oryzae genome, but instead, a putative fungal specific peroxin, Pex33p. Pex33p was also assigned as Pex14/17p, as the N-terminus of this protein is similar to the N-termini of Pex14p proteins, whereas its C-terminus shows similarity to yeast Pex17ps. Peroxisomes are astonishingly variable organelles, which proliferate rapidly facing to environmental stimuli. Peroxins in Pex11p family and Pex23p family are proteins related to peroxisome proliferation so far. Mopex23p and Mopex24p are homologous proteins of Pex23p family in M. oryzae.MoPEX33, MoPEX23 and MoPEX24 were deleted from wild type Guy11 Via Agrobacterium mediated transformation. The fusion fluorescent proteins for PTS1, PTS2 and mPTS were used to monitor the distribution of the peroxisome matrix and membrane proteins. The results indicated that PTS1-containing proteins were distributed partially in △mopex33-4 mutant. The virulence of △mopex33-4 is reduced than that of the wild type Guy11. We also show that the fatty acid metabolism is disorder, and the cell wall integrity and the ability to resistant the reactive oxygen species are reduced in △mopex33-4. This mutant showed reduction in vegetative growth, aerial hyphae generation, conidiation, spore germination and appressorium formation. The turgor pressure is also reduced in the appressoria of the mutant. So we think that MoPEX33 gene is necessary for the normal peroxisome matrix proteins transportion and pathogenicity in M. oryzae.However, the Phenotype and pathogenicity of the mutant △mopex23-10 and △mopex24-1 exhibited no significant difference to the wild type Guy11, so we speculated that the peroxisome proliferation mode of filamentous fungi is different from yeast.