Cloning And Functional Analysis Of Ras Gene In Signal Transduction Pathway Of Setosphaeria Turcica

Northern Corn Leaf Blight, caused by Setosphaeria turcica, is one of the most important diseases in corn planting area. Current research indicated that the growth of many plant pathogenic fungi, was subject to extracellular control signal transduction pathways, such as Ras, MAPK, cAMP and Ca2+ signals, especially the MAPK pathway on growth and development of plant pathogenic fungi and this signal transduction was an important pathogenic regulating factor. Ras protein was located in MAPK signal transduction pathway upstream, ras genes were highly conserved in evolution, widely existed in various eukaryotes, such as mammals, drosophila, fungi, nematodes and yeast. Genetics, biochemistry and molecular biology studies indicated that Ras in cells generated by stimulation of the signal transduction pathway in a central position. Therefore, in-depth study of the function of Ras protein was conducive to study the occurrence of disease, development and invasive mechanisms, the study of pathogenic fungi and host plants as well as the interaction between plant disease prevention and treatment also had important theoretical significance. Here we did some research on Ras protein of Setosphaeria turcica in its function regulating pathogenesis, the main results were as follows:1. As the basis of ras gene of the known plant pathogenic fungi designed primer which using PCR amplification. And then use the Setosphaeria turcica homologous ras gene fragments for Genome walking, amplify the ras gene sequence. The use of the BLASTX sequence analysis software, the results show that the homology of ras sequence in Pyrenophora tritici, Phaeosphaeria nodorum SN15, Magnaporthe grisea are 80%~90%.2. The specific inhibitors of ras gene manumycin A was used to study the fuction of ras gene in Setosphaeria turcica. The results showed the characteristics of hyphae and conidia of the fungus treated with manumycin A were similar with its wild-type isolate, but conidia germination time delayed, and the germ tube shorten; the number of conidia germination rate and cell adhesion declined markedly. With 20~120μmol/L concentration of manumycin A to deal with 6~36 h after the interval in the scope of this deal, the manumycin A and attachment of conidia germination inhibition of cell generated increases as the concentration, however, with the extension of the processing time decreased. 3. The use of DNAMAN software for further analysis of ras gene fragments restriction sites and based on plasmid pSO-Ⅰ. The construction of ras antisense expression vector of Setosphaeria turcica was for Ras function analysis.