Metagenomic analysis reveals the diversity and distribution of antibiotic resistance genes in thermokarst lakes of the Yellow River Source Area

Abstract

Thermokarst lakes form as the results of ice-rich permafrost thawing and act as important water resources in cold regions. However, the distributions of antibiotic resistance genes (ARGs) in thermokarst lakes are far less studied. Using metagenomic sequencing approach, we provided the first study to document ARGs in thermokarst lakes of the Yellow River Source Area on the Qinghai-Tibet Plateau (QTP). The results revealed that both sediment and water of the thermokarst lakes harbor diverse ARGs. Multidrug resistance genes were the most diverse, while rifamycin resistance genes were the most abundant with rpoB2 and rpoB genes having the highest proportion. Sediment samples contained more ARGs than water samples, but their composition differed between the two types of samples. However, the composition variations of sediment and water ARGs were closely correlated. The Sorensen dissimilarities of ARGs were controlled by strong turnover processes in sediment samples, and by turnover and nestedness in water samples. High contributions of nestedness were found between sediment and water samples. Moreover, ARGs in water had more significant relationships with environmental variables than that in sediment. Given the role of thermokarst lakes as important water resources in permafrost landscape, as well as intensifying influences of climate change and anthropogenetic activities, thermokarst lakes could bring potential ARG risks, warranting further investigation and evaluation.