广西北仑河口红树林底泥放线菌多样性及其抑制甘蔗鞭黑粉菌活性分析

Diversity of actinomycetes isolated from bottom mud of mangrove forest in Beilun Estuary of Guangxi and its antibacterial activity against Sporisorium scitamineum

【目的】分析广西北仑河口红树林底泥放线菌多样性及其次级代谢产物抑制甘蔗鞭黑粉菌活性,为挖掘放线菌新物种及其新型农用杀菌剂打下基础。【方法】选取6种分离培养基,采用稀释涂布法对广西北仑河口红树林底泥样品进行分离培养,ISP2培养基纯化菌株,基于16S rRNA序列分析样品中放线菌多样性,并以牛津杯法对分离得到的菌株进行抑制甘蔗鞭黑粉菌活性测定。【结果】经排重合并和16S rRNA序列比对分析,从广西北仑河口红树林底泥中共分离得到36株放线菌,隶属于6目9科12属,链霉菌属(Streptomyces)为优势菌属,共有5株菌株的16S rRNA序列与标准菌株的相似性低于98.00%,可能为潜在新物种。抑菌活性测定结果表明,36株放线菌中有22株菌对甘蔗鞭黑粉菌有抑制作用,占所分离放线菌总数的61.11%。【结论】广西北仑河口红树林底泥中蕴藏着丰富的海洋放线菌资源,具有开发成新型农用生防杀菌剂的潜力。

【Objective】The diversity of actinomycetes isolated from bottom mud of mangrove forest in Beilun Estuary of Guangxi and the antibacterial activity of its secondary metabolites against Sporisorium scitamineum were studied in order to lay a foundation for finding new actinomycetes species and the corresponding agricultural fungicides.【Method】Samples from bottom mud of mangrove forest in Beilun Estuary of Guangxi were isolated and cultured with the method dilution coating in six isolation media.Strains were purified with the culture medium ISP2.Diversity of actinomycetes was analyzed by 16S rRNA gene sequencing.The antibacterial activity of isolated strain against S.scitamineum were initially tested with the method of Oxford cup.【Result】There were 36 strains were isolated from bottom mud of mangrove forest in Beilun Estuary of Guangxi through removal of duplication,combination,and comparison of 16S rRNA gene sequence.The strains distributed in 12 genera,9 families and 6 orders;Streptomyces was dominant genus.The similarity of 16S rRNA gene sequences between the five strains and standard strain was bleow 98.00%.The result indicated the five strains were potential new species.The test result of antibacterial activity showed that among 36 actinomycetes strains,22 strains had antibacterial effectson S.scitamineum,accounting for 61.11%of total isolated actinomycetes.【Conclusion】The bottom mud of mangrove forest in Beilun Estuary of Guangxi is abundant with marine actinomycetes resources,which provides potential for development of new agricultural fungicides.