黄河兰州段河岸带土壤中微生物与耐药基因的赋存特征

Characteristics of Microorganisms and Antibiotic Resistance Genes of the Riparian Soil in the Lanzhou Section of the Yellow River

河岸带土壤是流域的重要组成部分,生物污染物赋存特性影响了流域水环境的污染治理.以农田、周山和工业用地为代表性土壤,探究黄河兰州段河岸带土壤中微生物群落结构、抗生素抗性基因(ARGs)及其遗传原件(MGEs)的赋存特征.结果表明,变形菌门、拟杆菌门和放线菌门为黄河兰州段河岸带土壤的优势菌门.河岸带土壤的微生物种群结构与土地利用类型存在相关性(P<0.05).细菌群落的α多样性指数由大到小依次为:农田>周山>工业.定量PCR结果表明,磺胺类ARGs为黄河流域兰州段土壤中的优势基因,其中sul1丰度最高,为其它检测ARGs的20~36000倍.工业类型土壤的ARGs中的总绝对丰度最高.主坐标分析(PCoA)显示ARGs的赋存特性与土地类型也有显著性关联(P<0.05),并且intl1与tnpA⁃04分别对磺胺类ARGs和四环素类ARGs的传播具有驱动效果.冗余分析(RDA)表明,黄河兰州段河岸带土壤中的无机盐离子和总磷的含量是改变微生物结构的主要理化因子,盐杆菌门和酸杆菌门是驱动ARGs结构变化的主要微生物菌群.

Riparian soil is a critical area of watersheds.The characteristics of biological contaminants in riparian soil affect the pollution control of the watershed water environment.Thus,the microbial community structure,antibiotic resistance genes(ARGs),and mobile genetic elements(MGEs)in the riparian soil of the Lanzhou section of the Yellow River were investigated by analyzing the characteristics of soil samples collected from farmland,mountains,and industrial land.The results showed that the Proteobacteria,Bacteroidetes,and Actinobacteria were the dominant phyla in the riparian soil of Lanzhou section of the Yellow River.The microbial structure in the riparian soil was significantly correlated with the land use type(P<0.05).Theαdiversity index of bacterial communities in land types was in the order of farmland>mountain>industry.Sulfonamide-typed ARGs were the most dominant genes in the soil of the Lanzhou section of the Yellow River Basin,among which the sul1 gene had the highest abundance,20-36000 times that of other detected ARGs.Moreover,the total absolute abundance of ARGs in industrial soil was the highest.Principal coordinate analysis(PCoA)displayed that the ARGs characteristics had a significant correlation with land types(P<0.05),and intl1 and tnpA-04 drove the diffuseness of sulfonamide and tetracycline ARGs,respectively.Redundancy analysis(RDA)demonstrated that the content of inorganic salt ions and total phosphorus in the soil of the riparian zone of the Yellow River Lanzhou section were the main environmental factors,modifying the distribution of the microbial structure.Halobacterota and Acidobacteriota were the main microflora that drove the structural change in ARGs.