Research On The Diversity And Biological Activity Of Culturable Actinomycetes In Soil Along The South Of Gaoligong Mountain

Gaoligong Mountain is characterized by complex topography,rich biodiversity and less human disturbance,which makes it of high research value of actinomycetes resources.Even though soil actinomycete resources have been studied for many years,the potential of soil actinomycetes to produce active substances is still underestimated.Based on years of research on soil actinomycete resources in the laboratory,from the perspective of pure culture actinomycetes,explore the diversity of culturable actinomycetes in the soil along the south of Gaoligong Mountain,and identify new actinomycete taxonomy units;Various types of functional genes and antibacterial activity screening methods are used to excavate bioactive potential strains.In addition,genome sequencing of higher potential strains and prediction of their biosynthetic gene clusters provide more effective strain resources for the development of lead compoundsFirstly,after pretreatment of the soil samples,actinomycetes were isolated using 4 types of media.A total of 522 actinomycetes were obtained,which were distributed in 7 orders,13 families,and 32 genera.Streptomyces and Rhodococcus are the dominant genus,with 299 and 71 strains,accounting for 57.3%and 13.6%.Potential new taxonomic units obtained from the four media are:12 strains of YIM medium 171,11 strains of YIM medium 91,16 strains of HV medium,and 5 strains of YIM medium 4.A systematic classification study of a potential new species was carried out by means of polyphasic classification.The strain YIM 123512 was identified as a new species of the genus Nocardioides and named Nocardioides flavescens sp.Nov.Then,522 strains of actinomycetes were deduplicated,and 346 strains of actinomycetes were selected for antibacterial activity and functional gene screening.In the antibacterial activity experiment,the positive detection rates of six indicator bacteria including Bacillus subtilis,Staphylococcus aureus,E.coli,Mycobacterium tuberculosis,Candida albicans and Aspergillus niger were 7.2%,5.5%,5.2%,2.6%,1.7%and 1.7%.The positive detection rates of Malacidin,Lugdunin,Teixobactin,Leinamycin,Glutarimide,Salinomycin,and Diterpenes were 1.4%,0%,0.5%,41.3%,4.6%,4.9%,and 16.8%Finally,combined with the antibacterial activity and functional gene screening results,5 strains of actinomycetes were selected for genome sequencing,and their secondary metabolite gene clusters were predicted through the antiSMASH prediction platform.The analysis results showed that these strains have a variety of valuable bioactive substances synthetic genes are worth our development and utilizationThis study shows that the southern edge of Gaoligong Mountain is rich in soil habitat actinomycetes with certain antibacterial activity and some valuable gene clusters of secondary metabolites,which can provide an important basis for the study of lead compounds and is worthy of further research.