Mining Of Secondary Metabolites In Three Streptomyces Based On Genomic Information

Streptomyces is a kind of biological resources with wide application prospects.The fermentation products of Streptomyces contain a large number of natural products with novel structures and significant activities,which are important sources for the development of new drugs.To date,most of the known active products have been obtained for the first time from Actinomycetes and are mainly derived from Streptomyces spp.Therefore,the study of Streptomyces sp.In this paper,three strains of Streptomyces isolated from different habitats in Xinjiang were selected as the research objects.Genomic mining technology was used to mine the genomic information of the strains,analyze the metabolic potential of the strains,use different media for fermentation,analyze and compare the secondary metabolites and their activity differences under different media conditions,and carry out the study of secondary metabolites.The main content is as follows:(1)The genome of Streptomyces TRM68022 was mined.The genome size of the strain was 6.93 Mb,and the GC content was 73.06%.There were 4743,2319 and 5074 protein coding genes annotated in COG,GO and KEGG databases.anti SMASH analysis showed that the strain contained 24 secondary metabolite biosynthetic gene clusters,including terpenes,polyketones,tetrahydropyrimidines,NRPS,lanthionin,ribosomal synthesis and post-translational modified peptides,which had the potential to mine secondary metabolites.Cluster 2.11 gene cluster of the strain was found to have a complete candicidin gene cluster,which was a polyene macrolide compound.TRM68291 has a genome size of 8.46 Mb and a GC content of72.27%.There were 5944,2392 and 5894 protein-coding genes annotated in COG,GO and KEGG databases.anti SMASH analysis showed that the strain contained 35 secondary metabolite biosynthetic gene clusters,which had the potential to mine secondary metabolites.TRM66233 has a genome size of 6.87 Mb and a GC content of 70.47%.There were 4779,2339 and 5371 protein coding genes annotated in COG,GO and KEGG databases.anti SMASH analysis showed that the strain contained 24 potential secondary metabolite biosynthetic gene clusters,which had the potential to mine secondary metabolites.(2)OSMAC(one strain many compounds)strategy was used to screen fermentation media of Streptomyces TRM68022,TRM68291 and TRM66233 with 15 media,combined with HPLC and activity detection.We found that TRM68022 produced secondary metabolites with a large amount of metabolism under corn meal medium.TRM68291 produced secondary metabolites with high metabolic amount when cultured in medium13.TRM66233 produced secondary metabolites with a large amount of metabolism when cultured in corn meal medium.The crude candicidin D was isolated from the active substance produced by TRM68022 strain by HPLC and LC-MS,which had antagonistic activity against Candida albicans.A known compound of diketone piperazines(cyclo-(R-Pro-Gly))was also obtained.A small molecular compound Pentatriacontane was obtained from the methanol extract of Streptomyces TRM68291.Corn flour medium was selected to expand the fermentation of Streptomyces TRM66233,and the fermentation products were separated and purified,from which two compounds were obtained.It was identified by magnetic resonance imaging as 1,3-benzodioxole-2-one-4-carboxylamide(1,3-benzodioxole-2-1-4-amide)and pyrrole-2-carboxylic acid(pyrrole-2-carboxylic acid),pyrrole-2-carboxylic acid showed a significant antagonistic effect against Shigella.To provide theoretical support for further study of three Streptomyces strains by comparing the abundance and antagonistic activity of secondary metabolites analyzed by HPLC under different media conditions.(3)In order to find more secondary metabolites,PPtase(phosphoryl mercaptoethylamine transferase)overexpression activation strategy was used to construct recombinant strain TRM68022-6 and TRM68291-5,but no activation signal was detected.The recombinant strain TRM66233-6 was successfully constructed and the activation signal was detected.It is planned to further mine the differential peaks produced by the three Streptomyces strains by expanding the culture pair for secondary metabolites.