Diversity Of Actinomycetes In Tailan River Of Xinjiang And Mining Of Secondary Metabolites Of Strain Against Jujube Black Spot Disease

The Tailan River has a unique basin climate and is rich in microbial resources.In this thesis,the silt samples collected from Tailan River were taken as the research object to study the diversity of culturable actinomycetes.Multi-phase classification and identification of two potential novel Streptomyces strains were carried out.The antagonistic active strains of the pathogen of jujube black spot disease（Alternaria tenuissima）were screened.A strain of actinomycetes TRM68291 with better inhibition effect was selected for isolation and identification of the secondary metabolites.The research results are as follows:13 kinds of separation media were used to isolate culturable actinomycetes from the samples of Xinjiang Tailan River silt.The isolated strains were analyzed by 16S rRNA gene sequence analysis,and the diversity of the isolated actinomycetes was counted.A total of 265 strains of actinomycetes were isolated,distributed in 5 orders（Streptomycineae,Pseudonocardineae,Streptosporangineae,Corynebacterineae,Micrococcineae）,8 families（Streptomycetaceae,Thermomonosporaceae,Pseudonocardiaceae,Nocardiaceae,Nocardiopsaceae,Promicromonosporaceae,Actinosynnemataceae,Jonesiaceae）,9 genera（Streptomyces,Actinomadura,Amycolatopsis,Nocardia,Nocardiopsis,Promicromonospora,Rhodococcus,Saccharothrix,Jonesia）of Actinomycetes,87 known species and 8 potential novel actinomycetes.The strain morphological characteristics,physiological and biochemical characteristics,chemical classification characteristics and genotype characteristics of two potential novel species of actinomycetes TRM68295 and TRM68348 were analyzed.And the strains TRM68295 and TRM68348 were identified as novel species of the genus Streptomyces,named Streptomyces albicerus（CCTCC AA 2018085^T=KCTC49272^T）and Streptomyces tailanensis（CCTCC AA 2018086^T=KCTC 49274^T）,respectively.The isolated actinomycetes were fermented in small batches,and the antibacterial activity of the actinomycete fermentation broth against the pathogen of jujube black spot disease was determined by agar diffusion method.65 strains of antagonistic active strains were screened,all of which were Streptomyces,accounting for 24.5%of the isolated actinomycetes.Through activity screening and HPLC analysis,it was found that Streptomyces levisi TRM68291 had good antibacterial activity and abundant secondary metabolites.Streptomyces TRM68291 was fermented at 28℃and 180 rpm using Am6 liquid medium as fermentation medium.The fermentation broth was enriched by AB-8 macroporous resin,and separated and purified by silica gel chromatography,gel chromatography,and liquid phase preparation,and 3 monomer compounds were isolated.Through ¹H NMR and ¹³C NMR spectral data,HSQC,HMBC two-dimensional spectral data,combined with comparison analysis of the microNMR database and spectral data in the literature,the three compounds were identified as:（1S,3S）-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid,（1R,3S）-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid and L-tryptophan.