Diversity And Predication Of Application Value Of Cultivable Actinomycetes Associated With Lichen In Three Regions Of Southwest Yunnan

Known as the biological kingdom,Yunnan is a province with the richest biodiversity in China and one of the hotspots in global biodiversity research.The unique geographical environment and climatic conditions have given birth to diverse and colorful lichen species,forming a colorful ecological community of Yunnan lichen.Lichen are symbiotic organisms consists of fungi and algae and/or cyanobacteria in the ecosystem.Apart from symbiotic fungi and algae,the lichens symbiosis system also includes some symbiotic actinomycetes.Actinomycetes have always been an important producer of natural antibiotics and active substances.In this study,lichens collected from Lincang,Pu'er and Xishuangbanna of Yunnan Province are taken as research objects,and to analyze the diversity and distribution of pure cultivate actinomycetes associated with lichens based on the perspective of pure culture,to test the antimicrobial activities and screen antibiotic functional genes of the representative actinomycetes,and genome mining of potential strains was carried out to predict the potential biosynthesis of actinomycete.According to the particularity of lichen fungi-algae symbiotic and isolation experience of our lab,three actinomycetes selective media were used to isolate actinomycetes through plate dilution method with adding the inhibitor combinations.A total of 436 strains of actinomycetes were isolated,of which 63 were isolated from 4 lichen samples collected from Lincang,266 were isolated from 16 lichen samples collected from Pu'er,and 107 were isolated from 17 lichen samples collected from Xishuangbanna.These isolates are distributed in 10 orders,19 families and 50 genera,reflecting that there are abundant actinomycetes associated with lichen.Streptomyces was distributed widely associated with lichen in Xishuangbanna,Streptomyces,Microbacterium,Agromyces and Promicromonospora were the prime groups in Pu'er lichen.On the basis of abundant community diversity of actinomycetes,42 potential new taxa were obtained,three strains of them were classified and identified by polyphasic taxonomy approach,determinating a new species of Naasia: Naasia lichenicola sp.nov.,a new species of Nakamurella: Nakamurella albus sp.nov.and a new species of Glaciibacter: Glaciibacter sp.nov.At present,there is only one species of Naasia and Glaciibacter,which belongs to the rare group.The results indicate that lichen is an important habitat source for the discovery of new species of actinobacteria.Total 340 strains of actinomycetes were screened for functional genes and antimicrobial activity.Among the 13 antibiotic functional genes,286 strains contained at least one of them,accounting for 84.1%.Among 6 different indicator strains tests,114 strains display antimicrobial activities against at least one of them,accounting for 33.5%.Combined with functional gene screening and antibacterial activity test results,seven actinomyces genome sequence were analyzed by the antiSMASH website to predict the biosynthetic gene clusters,the results showed that different actinomyces had the ability to synthesize different secondary metabolites with great differences.Among them,strain YIM 132580 of Streptomyces exhibits rich gene cluster diversity and has great biosynthetic potential for bioactive compounds.The results of present study show that there are abundant actinomycetes resources associated with lichen symbiosis in Yunnan province,and it has great potential to synthesize antibiotics and other bioactive substances,providing material basis and theoretical guidance for further development and utilization of actinomyces associated with lichen.