The Influence Of Gene14-3-3on Growth,Development And Pathogenicity Of Magnaporthe Grisea

The14-3-3proteins are described as highly conserved, acidic regulatory proteins that are present in all investigated eukaryotic organisms.14-3-3proteins dimer were formed by two homologous or heterologous monomers of30kD. Generally, there are two14-3-3genes in lower eukaryotes. When one of them was knockouted, the growth of strains were not changed, but the mutants lacked both are lethal. In yeast,14-3-3genes have impacts on growth, cell cycle and morphological changes, and they also were required in intracellular signaling pathway.Rice blast, caused by M.grisea, is the most devastating fungal pathogen disease of rice, accounting for more than10million tons of yield loss every year. M.grisea is a Pyrenomycete that produces fusiform, curved ascospbres in unordered asci within perithecia, and has a typital life cycle and infection cycle. Rice blast is considered as a model system for studying host plant-fungal pathogen interactions. The asexual spore will germinate in vitro and form one or more germ tubes. The germ tube apex swells after a short period of growth and forms appressorium. The penetration peg serves to carry the pathogen through the surface of the host and form the infection hypha.There are the main results of the infection of14-3-3genes in growth, development and pathogenicity of M.grisea as below:(1) In comparison with other fungal sequences in Magnaporthe grisea database,we found two14-3-3genes, which are RAD24and RAD25;(2) We constructed the knockouted vectors, and both of theâ–³14-3-3(1) andâ–³14-3-3(2) mutants using AMTM transformation methods were achieved;(3) The colonies ofâ–³14-3-3(1) andâ–³14-3-3(2) mutants were slightly reduced on CM and PA medium, and the hypha was a little aparse on PA medium;(4) Bothâ–³14-3-3(1) andâ–³14-3-3(2) mutants were sensitive to osmotic pressure especially in CM medium conteining0.5M sorbitol;(5) Amount and rate of the conidiation ofâ–³14-3-3(1) andâ–³14-3-3(2) mutants increased one more time than WT;(6) The pathogenicity of theâ–³14-3-3(1) andâ–³14-3-3(2) mutants had not changed compared with wild-type, and still had the ability to infect plant;(7) Conidial germination and appressorium formation ofâ–³14-3-3(1) andâ–³14-3-3(2) mutants were delayed compared to the wild-type;(8) Like other lower eukaryotic organisms, M.grisea could not grow on CM medium when two14-3-3genes were knocked out.14-3-3proteins are very important types of eukaryotic regulatory proteins. Till now There are few studies in filamentous fungi as it is a new research topic. Rice blast has been considered a model system for studying host plant-fungal pathogen interactions, so the methods of this research provide a new way to study other filamentous fungi.