土壤微生物敏感菌及信号调节途径对邻苯二甲酸二甲酯的响应

摘要

Dimethyl phthalate(DMP), a biotoxic organic compound, has been listed as one of the priority control pollutants by China's Environmental Monitoring Center and the USA Environmental Protection Agency.Soil microorganism can accurately and quickly respond to the changes of soil environment and soil contamination.Therefore,it is necessary to study the response of soil microorganisms to DMP.This study investigated the impact of dimethyl phthalate(DMP)on the microbial community structure,diversity and signal regulation pathway in soils through metagenome sequencing.DMP were used to treat uncontaminated soil,and the final concentration of DMP was 0,5,10,20,40 mg·kg-1. Then, the samples were incubated for 20 days in dark and sequenced by metagenome. The results showed that the growth of degradation of aromatic compound was promoted and the growth of the remainder strain was inhibited by DMP contamination.Inhibitory effect was positively correlated with DMP concentration. DMP decreased microbial community diversity in soils. The total abundance of ABC transporters, two-component system(TCS)and phosphotransferase system(PTS)genes were increased by DMP contamination. The gene abundance of relative enzymes also was enhanced along with the increasing DMP concentration. Therefore, DMP contamination changed microbial community structure, and disturbed ecological balance and soil health in soils. The ecotoxicological effect of DMP on soil is of scientific significance and practical value to optimize the service function of environmental ecosystem and improve the environmental quality.%邻苯二甲酸二甲酯(Dimethyl phthalate,DMP)是一类具有生物毒性的有机化合物,已被中国环境监测中心和美国环保署列为优先控制污染物之一.土壤微生物对土壤环境变化能够作出精准且快速的反应,并能预测土壤的污染状况.因此,研究土壤微生物对邻苯二甲酸二甲酯污染的响应显得十分必要.试验通过土壤微生物宏基因组测序,探讨了DMP污染对土壤微生物敏感菌的丰度、多样性及信号调节途径的影响.首先,用DMP处理未污染土壤,使DMP终浓度为0、5、10、20、40 mg·kg-1,然后,暗培养20 d,进行土壤宏基因组测序.结果发现与芳香族化合物降解相关的菌种的相对丰度受到DMP污染促进,而其余在土壤中占比例较大且变化较显著的菌种的相对丰度受到DMP的抑制,且抑制效应与污染物浓度呈正相关;DMP污染导致土壤微生物群落Simpon和Shannon多样性降低;土壤微生物的ABC转运系统、双组分系统(TCS)和磷酸转移酶系统(PTS)总基因丰度及相关酶的基因丰度均受DMP污染的促进.研究表明DMP污染改变了土壤微生物敏感菌种的丰度,干扰土壤微生物基因表达调控系统,进而有可能引起土壤生态系统失衡,影响土壤健康.阐述DMP对土壤微生物的生态毒理效应对优化环境生态系统服务功能、改善环境质量具有科学意义和实际价值.