Functional Analysis Of Three Putative Subtilase Protease Genes In Rice Blast Fungus

The rice blast disease, cause by Magnaporthe oryzae, is one of the most explosive diseases of rice and remain no lasting, sustainable control strategy. The interaction between M. oryzae and rice is a model for studying pathogenic fungi-plant interaction. To reveal the molecular mechanisms of this pathogen, will help to establish new control strategies for rice blast.Serine proteases are a family of proteolytic enzymes, with serine as their catalytically active sites, which widely exist in eukaryotes, bacteria and viruses. During the infection of M.oryzae, some serine proteases can be secreted into the extracellular, so that they were considered as potential pathogenic factors. In the rice blast fungus, serine protease family refers to the subtilase family. In this paper, three genes MGG₀9817.7、MGG₀8415.7 and MGG₀3870.7 of putative subtilase proteases were selected to be studied. Three MGG₀3870.7 knock-out mutants and one MGG₀8415.7 knock-out mutant were obtained by technology of homological recombination. The phenotypes analysis showed that the colony morphology, growing rate and pathogenicity of the MGG₀3870.7 knock-out mutants had no significant difference with the wild type Guy 11, but the conidiation was significantly reduced, the knock-out mutant of MGG₀8415.7 was as normal as Guy11. These results can be explained that these two genes may be not associated with the growth and pathogenicity of M. oryzae, or because of gene redundancy, other homology gene complement the function of these two genes.