Diversity And Antimicrobial Activity Of Actinobacteria Isolate From Mangrove Rhizosphere Mud In Maowei Sea, Guangxi

Objective:To study the diversity and antimicrobial activity of actinobacteria,the actinobacteria isolated from plant rhizosphere mud in Maowei sea Mangrove Reserve of Guangxi Zhuang Autonomous Region were studied.Method:Actinobacteria were isolated by using standard serial dilution plating method with 10 kinds of isolation medium.The sequences of 16 S r RNA gene were obtained by PCR amplification.The phylogenetic trees were constructed by adjacency method,and the diversity of actinobacteria was studied by homology analysis.Selected 12 susceptible strains and resistant strains of Staphylococcus aureus,Enterococcus faecalis,Acinetobacter baumannii,Klebsiella pneumoniae,Escherichia coli and Pseudomonas aeruginosa.The antimicrobial activity of fermentation broth by extracted ethyl acetate and mycelia were studied by paper disc diffusion assay with organic layer and water layer and acetone extraction.Results:244 actinobacteria were isolated and purified from 8 soil samples of mangrove plant rhizosphere mud.They were distributed in 5 orders,14 families,29 genera.Microbacteriaceae includes five genera:Agromyces、Agrococcus、Microbacterium、Leifsonia and Amnibacteriu;Micrococcaceae includes five genera:Kocuria 、 Arthrobacter 、Sinomonas 、 Micrococcus and Pseudarthrobacter;Streptomycetaceae includes two genera:Streptomyces and Kitasatospora;Intrasporangiaceae includes three genera:Terrabacter、Intrasporangium and Phycicoccus;Demequinacea includes Lysinimicrobium and Demequina;Promicromonosporaceae includes two genera:Cellulosimicrobium and Brachybacterium;Cellulomonadaceae includes one genera:Cellulomonas;Micromonosporaceae includes one genera:Micromonospora;Nocardiaceae includes two genera:Rhodococcus and Nocardia;Nocardiaceae includes one genera:Mycobacterium;Nocardiopsaceae includes one genera:Nocardiopsis;Streptosporangiaceae includes two genera:Microbispora and Sphaerisporangium;Thermomonosporaceae includes two genera:Actinoallomurus and Actinomadura,and the dominant genera were Streptomyces and Micromonospora.The highest similarities and the validly described of 16 S r RNA gene sequence between srtain S4B6-851 and Amnibacterium kyonggiense KSL51201-037T(FJ527819),between srtain K6A10-57 and Streptomyces polymachus T258T(KM229363),between srtain K7B1-327 and Lysinimicrobium pelophilum NBRC 109393T(BBLY01000002)and between srtain and Arthrobacter pascens DSM 20545T(X80740)were97.78%,98.30%,98.52%,and 97.77%,respectively.The results indicated thefour strains were potential new taxa.83 strains were selected from 244 strains of actinomycetes for fermentation,the results of screening with antibacterial ability of the 13 strains of actinomyces;The results of re-screening of antimicrobial activity showed that the positive rate of antimicrobial activity of 83 actinomycetes was 71.1%.Conclusion:The diversity and antimicrobial activity of actinobacteria in plant rhizosphere mud of Maowei sea Mangrove Reserve in Guangxi are abundant.