Diversity Of Microbial Community And Distribution Of Antibiotic Resistance Genes In Lakes From Wuhan And Tibet

With the acceleration of urbanization,the problem of lake pollution is becoming more and more serious,and the lake ecosystem is facing great challenges,mainly manifested in heavy metal pollution,antibiotic resistance genes(ARGs)pollution,lake eutrophication,and so on.As an important part of the lake ecosystem,microorganisms play an important role in energy flow and material circulation.The microbial community structure of lakes is easily affected by environmental factors such as p H,total carbon,temperature,nutrients,heavy metals and so on,and the responses of microbial community to environmental factors are different in different regions.As an important carrier for the spread and transfer of ARGs,lake microorganisms affect the occurrence of ARGs in lakes.This paper selected four lakes with low altitude in Wuhan and four high-altitude lakes in Tibet as the targets.16 S r RNA gene and metagenomic sequencing were conducted to analyze the bacterial communities and ARGs in lake water and sediments.For analysis of ARGs,16 S r RNA gene copy number was normalized to the abundance of ARGs.The aim is to clarify the microbial community structure and ARGs composition and diversity in these 8 lakes,and at the same time analyze the relationship between microbial community structure,ARGs and environmental factors,and reveal the role of environmental factors in shaping microbial communities and ARGs.According to the correlation between microbial community and ARGs,potential microbial hosts of ARGs were identified.The obtained results of this study are as follows:(1)The diversity of the microbial community in the lakes showed the order of SW>SX>WW>WX,It may be concluded from beta diversity analysis that the microbial communities in Tibetan lakes had a high degree of homology,and the difference in microbial community structure in the water and sediments of Tibetan lakes was lower than that in Wuhan lakes.(2)A total of 33 bacterial phylum were detected in Tibet and Wuhan lakes.Tibet and Wuhan lakes were similar in composition.Proteobacteria,Actinobacteria Bacteroides and Firmicutes accounted for 90.2%?99.2%of the microbial communities in lakes from Wuhan and Tibet lakes.Actinobacteria and Proteobacteria were the main bacteria in lake water and sediments respectively.Among the dominant bacteria(>1%),the relative abundance in lake sediments was greater than that in lake waters,except for Acidobacteria.(3)Correlation analysis between microbial community diversity index and environmental factors found that in the water environment,the correlation between the Chao1 index of lake microbial community and environmental factors was not significant,while in sediments Chao1 had a significant negative correlation with electrical conductance,salinity,altitude,heavy metal As,and a significant positive correlation with Co.Shannon index was significantly positively correlated with altitude in lake water,and Shannon index and Simpson are both significantly positively correlated with total carbon and Pb,while they are significantly negatively correlated with Hg and As.In sediments,Shannon index and Simpson index were significantly positively correlated with the correlation of other environmental factors except for temperature.Altitude,heavy metals,and temperature were important factors affecting the distribution of microbial communities in lakes.(4)A total of 21 ARGs types and 313 ARGs subtypes have been detected in lakes.Bacitracin and multidrug resistance genes are the main types of ARGs in lake water and sediments respectively.bac A is the main ARGs subtype in lakes,accounting for 14.30%?61.35% of the total abundance of ARGs in lakes.The abundances of resistance genes such as macrolide-lincosamide-streptogramin,rifamycin,sulfonamide and beta-lactam related to human activities were higher than those in Tibetan lakes.Among them,the abundances of rifamycin resistance genes and sulfonamide resistance genes in Wuhan lakes were 3.5 times and 6 times those of Tibetan lakes.The relative abundance of ARGs in lake sediments was significantly higher than that in lake water bodies(P<0.01).There was no obvious difference in the diversity and total abundance of ARGs between Wuhan and Tibet lakes,and Tibet lakes are also important reservoirs of ARGs.(5)The response of ARGs to environmental factors varied with lake media and lake types.Most ARGs in lakes were significantly related to altitude and heavy metals.RDA analysis found that total carbon and temperature were the main influencing factors affecting ARGs in Wuhan lakes,while Hg,As and altitude were the main environmental factors affecting the occurrence of ARGs in Tibetan lakes.Acidobacteria,Proteobacteria and Firmicutes were potential microbial hosts for important ARGs in Wuhan and Tibet lakes.In summary,there were differences in the composition and abundance of microbial communities and ARGs in different media in Wuhan and Tibet lakes.Altitude,heavy metals and temperature,etc.were important environmental factors that affect microbial community structure and ARGs occurrence in lakes.This study provided a scientific basis for controlling the evolution of antibiotic resistance and the spread of ARGs,and was of great significance for ecological security protection of lakes.