Spatial Distribution Pattern Of Microbial Community And Resistance Genes In Boqing River

Microbial diversity and community structure are of great importance to aquatic ecosystems.Changes in the aquatic environment can affect the structure and diversity of microbial communities,which in turn impact ecosystem function.In areas where non-ferrous metal is produced,the structure and composition of microbial communities in water bodies can be affected by environmental factors such as heavy metal pollution.Under the selective pressure of heavy metals,microorganisms can produce antibiotic resistance genes(ARGs)through co-selection or cross-selection,resulting in changes in ARG abundance and diversity in aquatic environments.However,the distribution characteristics of microbial communities and ARGs in water bodies in non-ferrous metal production zones and their driving factors are still unclear.Boqing River is an important tributary of the Yellow River located in Yuanqu County,Yuncheng City,Shanxi Province.The river passes through villages,the copper tailings pond,towns,and farmland before emptying into the Yellow River in the downstream region,with distinct regional characteristics.In this study,water was collected from 13 typical sites along the Boqing River to analyze the response relationship between microbial community and ARG abundance,diversity,and environmental factors,and to reveal the main factors influencing the distribution of microbial communities and ARGs in the Boqing River water body.The results are as follows:(1)In the water body of Boqing River,a total of 3261 OTUs were detected,belonging to 43 phyla and 929 genera.Among them,there are 14 dominant bacterial phyla,with Proteobacteria,Actinobacteriota,Bacteroidota and Firmicutes as the dominant groups,and 76 dominant bacterial genera,with Acinetobacter,Limnohabitans,Pseudarthrobacter and Flavobacterium as the dominant groups.The richness and diversity of the bacterial community in the tailings pond(S4)and its adjacent water bodies(S3,S5)were lower,while those in the downstream in the downstream of Boqing River(S10,S11,S12)increased significantly.This diversity distribution may be related to the physicochemical properties of the water body.The content of heavy metal Cr at the tailings pond outlet(S5)was significantly higher than that at other sampling points(P < 0.05);the content of Cd near the tailings pond(S3,S4)was significantly higher than that at other sampling points(P < 0.05),while the lowest values of Cu,Zn,and Hg occurred at S12 in the downstream of Boqing River.(2)Pearson correlation analysis found that in the water body of Boqing River,heavy metal Cu was significantly negatively correlated with Shannon index of bacterial community(P < 0.05),and Cr and Hg were significantly negatively correlated with richness index of bacterial community(P < 0.05),indicating that these heavy metals play an important role in the process of bacterial construction in Boqing River;Heavy metal Cd was significantly negatively correlated with Acidobacteriota and Actinobacteriota(P < 0.05),and Cu was significantly negatively correlated with Proteobacteria,Patescibacteria and Chloroflexi(P < 0.05),Cu,Cr,Cd were significantly negatively correlated with CL500-29-marine-group(P < 0.05).As was significantly positively correlated with Bacteroidota(P < 0.05),and was significantly positively correlated with Flavobacterium of Flavobacteria and Arenimonas of Proteobacteria(P < 0.05).Co-occurrence network analysis found that As had co-occurrence with eight dominant genera including Arenimona,which indicated the adaptability of Arenimona in the As environment.(3)A total of 196 ARGs were detected in the water body of Boqing River,among which aac,aad,aph,and str of Aminoglycosides,bla,cph,and fox of Beta＿Lactamase,sul2,fol A of Sulfonamides,and tet A,tet G,tet M,and tet X of Tetracyclines had high abundance;The abundance of Sulfonamides,Vancomycin,Aminoglycosides,Beta＿Lactamase,Tetracyclines,and MLSB ARGs in the urban center(S6)water body was significantly higher than that at other sampling points(P< 0.05).The abundance of ARGs of Sulfonamides,Aminoglycosides,Tetracyclines,FCA and MLSB in the sewage treatment plant(S9)was significantly higher than that of other sampling points(P < 0.05).The possibly due to that these areas are affected by factors such as urban domestic sewage,industrial wastewater,and farmland runoff.(4)The correlation analysis between environmental factors and ARGs found that the heavy metal Zn was significantly positively correlated with Aminoglycosides,MLSB,Beta＿Lactamase and Vancomycin ARGs(P < 0.05),indicating the importance of Zn in the selection of these categories of ARGs;TC was significantly positively correlated with Sulfonamide and Tetracycline ARGs(P < 0.05);As was significantly positively correlated with tet M,tet G of Tetracycline ARGs,aac,aad,str of Aminoglycoside ARGs,and sul2 of Sulfonamide ARGs(P < 0.05).Among the dominant bacterial phyla,the Gemmatimonadetes was significantly positively correlated with Aminoglycosides,MLSB,Beta＿Lactamase,and Vancomycin ARGs(P < 0.05),and the Bacteroidota was significantly positively correlated with the Tetracycline ARGs(P < 0.05).The significant positive correlation(P < 0.05).Among As,Bacteroidota,and Tetracycline ARGs indicated that As was the key influencing factor for the spread of Tetracycline ARGs in Bacteroidota.In summary,the distribution of bacterial communities and antibiotic resistance genes in the water body of Boqing River is not only related to the distribution of tailings ponds,urban areas,farmland and sewage treatment plants,but also affected by environmental factors such as the content of heavy metals in the water.While changing the bacterial community structure,environmental factors such as heavy metals can also cause the selection of bacterial ARGs in the water body,increasing the risk of bacterial ARGs spreading in the aquatic environment.This study is of great significance to the construction of ecological civilization in the Yellow River Basin.