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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。
Aim To study the diversity of actinomycetes in rhizosphere soil of Maweihai mangrove plant and screen antibacterial activity to lay the foundation for the discovery of new actinomycetes and new agricultural biocontrol agents. Methods Actinomyces was isolated from 25 samples of mangrove soil using traditional methods of coating and compound nutrient composition. The sequence of 16S rRNA gene was amplified by PCR and the diversity of actinomycetes was studied by constructing phylogenetic tree The inhibitory activity of antagonistic and spore germination of two species of Fusarium oxysporum by actinomycete fermentation broth and ethyl acetate extract concentrate was analyzed by disk diffusion method. Results A total of 117 actinomycetes strains were obtained by row weighting. Sequence alignment of 16S rRNA gene revealed that 117 actinomycetes were found in 19 genera of 10 genera in 6 subtypes. Besides Streptomyces spp. Micrococcus, Gordonia, Corynebacterium, Nocardia and Plant Actinomyces sp.; Fusarium oxysporum antagonistic activity test surface, a total of 23 actinomycetes in at least One antibacterial activity test showed positive, the total positive rate was 19.66%. Conclusion There are abundant actinomycetes resources in the rhizosphere soil of Maweihai mangroves in the Beibu Gulf of Guangxi, which has the potential of discovering new species and new agricultural biocontrol agents.