Functional Analysis Of Some Putative E3Ubiquitin Ligases In Magnaporthe Grisea

Ubiquitination is one of the modifications in post-transcription of genes. Ubiquitination on target proteins is the signal of cellular protein degradation, in which process the ubiquitin ligase E3is one of the key enzymes. E3ubiquitin ligase involves in cell cycle regulation, tumorigenesis, cell proliferation, apoptosis, signal transduction, cell immunity, growth and development, inflammatory response and regulation of DNA replication and repair. We here studied the function of E3ubiquitin ligase in Magnaporthe oryzae.There are11E3ubiquitin ligases annotated in the genomic database of Magnaporthe oryzae, all of which have the conservative domains. Then, we obtained knockout mutants of four genes through the approach of homologous recombination. Further, we analyzed the phenotype of these knockout mutants. It showed that the mycelia growth of knockout mutants of four genes reduced slightly. The defect phnotypes such as the decrease of conidiation, the delay of germinmation and appressorium, as well as decrease in infection have been observed in the knockout mutants of Mgg₀3841.6and Mgg₀3252.6. The pathogenicity of these two knockout mutants decreased dramatically. These results suggest that ubiquitin-proteasome pathway may have important role in vegetative growth, spore germination, appressorium formation and pathogenesis in Magnaporthe oryzae.