| Rice blast disease caused by Magnaporthe oryzae, is one of the three major diseases,has become a threaten to the safety of the global rice. Therefore the control of rice blast is always an important subject in the production of rice. Relying only on the use of disease-resistant breeding and high yield and superior quality breeding can not effectively prevent the occurrence of the disease. Therefore understanding and mastering the pathogenic molecular mechanisms during growth,development is an important prerequisite for the control of pathogens.With the publication of the complete genome sequence of rice blast fungus,using molecular biology methods to research function of pathogenicity related gene is more and more convenient.This provides the basis for finding new fungicides target.Chromatin assembly and remodeling plays an important role during the repair of DNA damage in eukaryotic cell. Chromatin and chromosomes in the nucleus are different forms of the same substance formed by nucleosome through helical, coiled, compression. An octamer of the four histones H2A, H2B, H3 and H4 is the basic unit of eukaryotic chromatin. Histone assembled into nucleosomes is An important step during the process of transcription, replication and repair of DNA damage. Histone acetylation plays an important role in the early formation of chromatin structure. Newly synthesized histone are acetylated immediately and then assembled into chromatin. In Saccharomyces cerevisiae, deletion of histone acetyltransferase Hatl cause chromatin structure defects in the telomeric silencing.At the same time the mutant is highly sensitive to DNA damaging agents such as MMS. In Candida albicans, deletion of histone acetyltransferase Hatl leads to the change of morphology.The mutant shows higher sensitive to DNA damaging agents such as MMS、 EMS、4-NQO and UV, Hatl plays an important role in the process of DNA damage repair.In the first chapter of this article, We characterized MoHatl in M. oryzae, a homolog of Hatl in S. cerevisiae, MoHATl was over expressed during infected stage at 8h. The growth rate of ΔMohatl mutant was significantly reduced. The ΔMohatl mutant also exhibited defect in conidiation. Rice and barley leaves were inoculated with spore suspension,the results showed virulence of Magnaporthe oryzae significantly decreased. We also discover that the ΔMohatl mutant is sensitive to DNA-damaging agent such as MMS,also the ΔMohatl mutant showed highly sensitive to caspofungin(CASP). The expansion of invasive hyphae were inhibited. MoHAT1-GFP was introduced into the ΔMohatl mutant. the GFP signal was examined under an epifluorescence microscope, at the same time DAPI staining showed that MoHat1-GFP is mainly localized to the nucleus. The results through the above indicated MoHatl was involved in regulating the growth and development, the repair of DNA damage and pathogenicity in Magnaporthe oryzae.bZIP (basic leucine zipper, bZIP) transcription factors are named as their leucine zipper domain and widely distributed in microbes, plants, insects and animals. bZIP protein is not only transcription factor but also one of the most conservative and largest types of repressor protein. In plants, bZIP protein is not only involved in morphogenesis, storage gene expression in seed, the control for organ formation but also related to a variety of other biological processes,such as flower development, plant growth, bacteria defense, damage, optical signal and response to various environmental stresses. The second chapter mainly studied the other five bZIP transcription factors MoBZIP1、MoBZ1P2、MoBZIP3、 MoBZIP12、MoMEAB,founding that the deletion of MoBZIP1、MoBZIP2 and MoBZIP3 lead to an increase of sporulation; The deletion of MoBZIP12 and MoMEAB lead to decreased sporulation;MoBZIP12 was involved in the regulation of conidia morphology; MoMEAB was involved in nitrogen utilization in Magnaporthe oryzae. These five genes did not affect the pathogenicity of Magnaporthe oryzae. |
PDF Full Text Request