目的研究茅尾海红树林植物根际土壤放线菌多样性并进行抗菌活性筛选,为发现放线菌新物种以及新农用生防菌奠定基础。方法采用传统涂布分离方法和复合营养成分培养基,从25份红树林土壤样品中分离放线菌;通过PCR扩增菌株16S r RNA基因序列,并通过构建系统发育树研究放线菌多样性;采用纸片扩散法分析放线菌发酵液和乙酸乙酯萃取浓缩液对2种尖孢镰刀菌菌体拮抗和孢子萌发抑制活性。结果通过排重获得117株放线菌,16S r RNA基因序列比对分析表明117株放线菌分布于6个亚目10个科19个属,除优势菌属链霉菌属外,还发现纤维微球菌属,戈登菌属,栖白蚁菌属,拟诺卡菌属和植物放线孢菌属等稀有放线菌属;尖孢镰刀菌拮抗活性试验表面,共有23株放线菌在至少1个抗菌活性检测中显示为阳性,总阳性率为19.66%。结论广西北部湾茅尾海红树林根际土壤中存在丰富的放线菌资源,具有从中发现新物种和新型农用生防菌的潜力。Objective To investigate the biodiversity and bioactivity of anti-Fusarium oxysporum of actinobacteria isolated from mangrove soil in Maowei sea in Guangxi Province. Methods Actinobacteria were isolated from a total of 25 soil samples by traditional plate dilution method only using one isolation media containing nutritional composition. Diversity of culturable actinobacteria were analyzed based on comparison of 16S rRNA gene sequences. The antiftmgal activity of ethyl acetate extracts from the fermentation broth and crude fermentation broth of the strains were tested by disk diffusion method. Results A total of 117 actinobacteria strains were distributed in 19 genera affiliated with 10 families of 6 orders, including Streptornyces, Cellulosimicrobium, Gordonia, lsoptericola, Nocardiopsis, Plantactinospora, in which Streptomyces was the dominant genera. Twenty-three strainsexhibited positive results in at least one antifungal assay against mycelia growth or spore germination, and the total positive rate was 19.66%. Conclusion The study indicated that the abundance of culturable actinobacteria with antibiotic activity to Fusarium oxysporum in mangrove soilde served further exploration and research for biocontrol strains.国家自然科学基金(No.31260004,31660005)； 南宁市科技局项目(No.20153330)； 广西民族大学相思湖青年学者创新团队资助项目(No.201406
