西安市北郊污灌区土壤中抗铅链霉菌的多样性分析

Diversity of Lead-resistant Strains of Streptomycetes Isolated from Soil of Sewage Irrigation Area in Xi'an Northern Suburb

从西安市北郊污灌区采集土样,用添加K2Cr2O775μg·mL-1和青霉素2μg·mL-1的高氏1号、HV和SC固体培养基分离到120株具有链霉菌特征的放线菌。采用浓度梯度法,用含Pb2+培养基对分离菌株进行筛选,得到50株抗铅链霉菌。在抗铅能力实验结果的基础上,选取14株抗性较强链霉菌代表菌株进行形态培养特征、生理生化和16SrDNA基因序列相似性等分析。结果表明,14株代表菌株可归为6个不同的颜色类群,其表型特征与生理生化性质和链霉菌相符合,在系统发育树上处于8个不同的进化分支。菌株HQ0031与已知链霉菌相似性差异较大,可能为链霉菌属内1个潜在新种。研究表明西安市北郊污灌区土壤中抗铅链霉菌具有丰富的多样性,可为重金属污染环境的生物修复提供有益的微生物资源。

Totally 120 actinomycetes with cultural characteristics of Streptomycetes were isolated from soil samples of sewage irrigation area in Xilan northern suburb by Gause＇, HV and SC medium which were added with K2Cr207 75 μg·mL^-1 and Penicillin 2 μg·mL^-1. 50 anti-lead strains were screened from the mediums which were mixed with Pb （NO3）5 through concentration gradient. Then 14 strains which had higher tolerance were selected as representative strains for morphological, physiological characteristics and 16S rDNA gene phylogenetic analysis. The results showed that they were assigned to 6 color groups and in accord with Streptomycetes＇ morphological and physiological characteristics; there were 8 distinct branches in phylogenetic tree, while strain HQ0031 was far away from the branches and it would be a new Streptomycetes species. It could be concluded that there were abundant microbial diversity among the anti-lead Streptomycetes in sewage irrigation area in Xi＇an northern suburb and that would provide new resources for bioremediation of the soil that was polluted by heavy metal.