Functional Analysis Of 4 BZIP Transcriptional Factors During The Development And Pathogenicity Of Magnaporthe Oryzae

Rice blast caused by the filamentous ascomycetous fungus Magnaporthe oryzae is the most destructive disease of the rice, severely threats to global food security. Currently, the main measures of controlling the disease are choosing the resistant rice cultivars or using the fungicides. The resistant cultivars lose the resistant easily after a few years because of variation of the pathogen races. Therefore, it is still a durable problem to prevent and control the disease. In order to slove this problem, we must understand its regulatory mechanism in the process of growth and pathogenesis. However, both of the genome sequences of rice and Magnaporthe oryzae are available, some pathogenesis-related genes were discovered, that provide a new platform to understand molecular pathogenesis at the genome level.A large number of transcription factors have been found in plants and pathogens. The basic leucine zipper domain （bZIP） transcription factors are widely present in eukaryotes, including plants, animals, microorganisms. They are related to gene expression and regulation. The bZIP transcription factor is conserved, contains a basic region and a leucine zipper region.In the rice blast fungus M. oryzae,21 bZIP transcription factors have been found. Guo found that MoAp1 and MoAtf1, homologs of Pap1 and ATF/CREB that regulate the oxidative stress response in Schizosaccharomyces pombe, were involved in development and pathogenicity. In this paper, we investigated the biological function of MoFCR3（MGG₀2632）, a homolog of Candida albicans FCR3（for fluconazole resistance 3） and MoBZIP6（MGG₀4009）, MoBZIP7（MGG₀7305）, MoBZIP10（MGG₀6131） in the development and pathogenicity, especially the last one. Results showed that the mutant strains ΔMofcr3、ΔMobzip6、ΔMobzip7 were consistent with the wild type strain Guy11 in conidium formation and pathogenicity except growth rates.While mutant strain ΔMobzip10 showed a defect in asexual development, a lower percentage of appressorium formation, a decreased penetration efficiency, slower vegetative and invasive hyphal growth, as well as fewer lesions on the leaf of rice or barly compared to the wild type. Additionally, the merged image of GFP and DAPI staining showed that MoBzip10 localized in the cell nucleus. In conlusion, the bZIP transcription factor MoBzip10 is involved in the growth, development and pathogenicity of M. oryzae.