华中地区水库沉积物重金属抗性基因的赋存特征及影响因素分析

环境中重金属抗性基因（Metal resistance genes，MRGs）的迁移转化作为环境及生态领域的重要研究内容近年来备受关注，但目前环境中重金属是否是MRGs的重要驱动因素则尚不明确.本研究采用宏基因组技术对华中地区水库沉积物MRGs进行了定量，并分析了不同形态重金属在MRGs迁移转化过程中起到的作用.结果表明，trcop （抗Cu基因）及arsM （抗砷基因）是水库环境中的主要MRGs，供水水库之间MRGs分布并无地域性差异.czrA （多抗基因）的潜在宿主菌较为广泛，trcop及arsM很可能位于同一种可移动遗传元件上进行水平转移.重金属总量与MRGs之间并无明显联系，而可交换态及碳酸盐结合态（B1）则是环境中MRGs的重要驱动因素.

Distribution pattern and influencing factors of heavy metal resistance genes in reservoir sediment of central China

The migration and transformation of heavy metal resistance genes (MRGs) in the environment has attracted much attention in recent years. However, it is not clear whether heavy metals in the environment are important drivers of MRGs in the environment. In this study, metagenomic technique was adopted to determine MRGs abundance in the water supply reservoirs of Central China. Moreover, the role of heavy metal fractions in MRGs dissemination was analyzed. The results indicated that trcop (conferring Cu resistance) and arsM (conferring As resistance) were the main MRGS in the reservoir environment, and there wasno regional difference in the MRGs distribution in the reservoirs. There were a wide range of potential host bacteria of czrA (conferring resistance to multiply heavy metals). trcop and arsM were likely to transfer horizontally on the same mobile genetic element. There was no obvious relationship between the total heavy metal total contents and MRGs, while exchangeable and carbonate bound fraction of heavy metals (B1 fraction) were the important driving factors of MRGs in the environment.