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研究旨在揭示黄河三角洲贝壳堤放线菌多样性,以便从中寻找新的具有生物防治功能的微生物资源。采用3种分离培养基,利用稀释平板涂布法对贝壳堤土壤样品进行分离;通过形态特征、生理生化实验及16S rDNA基因测序对放线菌进行了分类鉴定。结果表明分离到的174株放线菌分属于10个科,13个属,其中链霉菌属(42%)和拟诺卡氏菌(11%)为优势菌属。16S rDNA基因分析表明,61%的菌株与已知菌的相似性都在99%以下,其中菌株BK-17的16S rDNA序列与同源性最近的菌株相似率仅为95.2%。以2株细菌和5株植物病原真菌作为指示菌,进行了抑菌活性测定,有94株至少对1种指示菌有抑菌作用,有8株对7种指示菌都有很强的拮抗作用。以上研究结果表明黄河三角洲贝壳堤土壤中存在丰富的放线菌资源,存在很多潜在的新菌种和活性菌株,有进一步研究和开发的价值。
The purpose of this study is to reveal the diversity of actinomycetes in the Yellow River delta shingle so as to search for new microbial resources with biological control functions. Three kinds of isolation media were used to separate shell soil samples by dilution plate coating method. The actinomycetes were identified by morphological, physiological and biochemical experiments and 16S rDNA gene sequencing. The results showed that the 174 strains of actinomycetes isolated belong to 10 families and 13 genera, among which Streptomyces (42%) and Nocardia pseudonocardi (11%) are the dominant bacteria. 16S rDNA gene analysis showed that the similarity of 61% strains with known bacteria was less than 99%. The 16S rDNA sequence of strain BK-17 was only 95.2% similar to the closest homologous strains. Two strains of bacteria and five strains of plant pathogenic fungi were used as the indicator bacteria to determine the antibacterial activities, 94 strains showed antibacterial activity against at least one indicator bacteria, and 8 strains showed strong antagonism to the seven indicator bacteria . The above results show that there are abundant actinomycete resources in the soil of the Yellow River delta embankment, and many potential new strains and active strains exist, which have further research and development values.