Marine Streptomyces Genetic Transformation System And Gene Screening Of Secondary Metabolites

70% of the area of the earth’s surface is covered by ocean, marine environment has diversity, which makes marine streptomycetes living environment more complex than the terrestrial streptomycetes, and this complex and changing environment gives marine streptomycetes diversity of species, genetic and ecological functions.With the successful gene clone from Streptomyces, Streptomyces genetic transformation system will enter a rapid development stage, more and more people began to focus on scientific research and development of Streptomyces. Establishing a perfect genetic transformation system of Streptomyces is important to antibiotic research, especially to antibiotic biosynthetic gene cluster cloning, identification and analysis. Streptomyces genetic transformation system plays an important role in antibiotic biosynthetic genes clone, antibiotic biosynthetic pathway elucidation, gene expression and regulation. It also provides a theoretical basis for discovering novel drugs, antibiotic synthesis and increasing yield. In this study, based on terrestrial Streptomyces genetic transformation systems, two plasmid vectors pJTU1278 and pHZ132 were used for genetic transformation in marine Streptomyces by conjugational transfer, which would provide insight into the genetic transformation and regulation of marine Streptomyces, functional gene identification of antibiotic biosynthetic gene cluster and combinational biosynthesis of antibiotics.Following terrestrial Streptomyces, marine Streptomyces become the important source of novel bioactive natural products. Marine Streptomyces have species, genetic and ecological functional diversity, which are the foundation of secondary metabolites diversity of marine Streptomyces. Streptomyces griseoaurantiacus M045 was isolated from Qingdao Jiaozhou Bay which can produce Manumycin-type compounds. Manumycin-type compounds show the significant antifungal bioactivities for crop pathogenic fungi, the effect is much better than some kinds of pesticides. Manumycin-type compounds also can inhibit melanoma and breast cancer significantly. According to the analysis of previous researchers, Manumycin-type compounds have a specific C5N and C7N core structure. Based on the genome of S. griseoaurantiacus M045, the 3,4-AHBA synthase gene and 5-aminolevulinate synthase gene were choosed as the selection genes to discover potential C7N and C5N structure compounds producers. These potential marine Streptomyces might produce manumycin-type compounds.Previously, we found that there are 8 gas vesicles protein coding genes in the S. griseoaurantiacus M045 genome, including gvpA, F, G, J, K, L, and O. Till now, there is no report about Gvp protein function in Streptomyces. In this study, the gvpA knockout vector was constructed and transferred into the marine Streptomyces M045 by conjugation transfer to identify the function of gas vesicle protein in the Streptomyces griseoaurantiacus M045.