Knock-out And Functional Analysis Of294Transcription Factor Genes In Magnaporthe Oryzae

Rice blast, caused by Magnaporthe oryzae, is one of the most serious diseases and brings about massive loss in rice cultivation. M. oryzae is a filamentous ascomycete fungus which can infect rice and many other gramineous plants such as wheat, barley and millet. In October2002, the genome sequencing of a rice pathogenic strain of M. oryzae,70-15, had been finished and supplied as a solid foundation for the studies of the developmental and pathogenic mechanisms.The gene expression of M. oryzae is regulated in multi levels, the transcription level regulation mainly caused by transcriptional factors functions as the first and most important step. Knock-out of transcriptional factors genes and then observing the phenotypes in null mutants is an effective strategy to study the functions of transcription factors and their interactions. The gene expression regulation is a complex network:a transcription factor can control the expression of lots of genes, and one gene could also be regulated by several transcription factors. Sutdies on only a few transcription factors can’t elaborate the complex regulation mechanisms of gene expression. So in this study, we want to knockout294genes to afford foundational and technical support of reseaches for gene expression process, signal transduction pathway and metabolic regulation network.294putative transcription factor genes of5transcription factor families (bHLH, bZIP, HMG, Homeodomain and Zn finger motif) were found in the rice blast fungus. The knockout vectors of277TF genes were constructed successfully and then transformed into M. oryzae through the Agrobacterium tumefaciens mediated transformation for homologous genes replacement. And the null mutants of171TF genes were identified by double PCR and qPCR.The phenotypes of the167transcription factor gene deletion mutants have been analysed. The null mutants of9TF gene deletion mutants growed slowly on CM medium,22TF gene deletion mutants produced few or even no conidia,2TF gene deletion mutants produced more conidia than the wild type. Especially, the null mutants of16TF genes showed weaker or no pathogenicity. To understand the regulation mechanism of transcription factors, continuing intensive studies on these null mutants in the future are necessary.