Pei Yaxin, Yu Zhengsheng, Ji Jing, Khan Aman, Li Xiangkai
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China.
Front Microbiol. 2018 Jan 25;9:38. doi: 10.3389/fmicb.2018.00038. eCollection 2018.
The Yellow River is the most important water resource in northern China. In the recent past, heavy metal contamination has become severe due to industrial processes and other anthropogenic activities. In this study, riparian soil samples with varying levels of chromium (Cr) pollution severity were collected along the Gansu industrial reach of the Yellow River, including samples from uncontaminated sites (XC, XGU), slightly contaminated sites (LJX, XGD), and heavily contaminated sites (CG, XG). The Cr concentrations of these samples varied from 83.83 mg⋅kg (XGU) to 506.58 mg⋅kg (XG). The chromate [Cr (VI)] reducing ability in the soils collected in this study followed the sequence of the heavily contaminated > slightly contaminated > the un-contaminated. Common Cr remediation genes and were detected in the XG and CG samples. qRT-PCR results showed that the expression of was up-regulated four and threefold in XG and CG samples, respectively, whereas the expression of was up-regulated 66- and 7-fold in the same samples after 30 min treatment with Cr (VI). The copy numbers of and didn't change after 35 days incubation with Cr (VI). The microbial communities in the Cr contaminated sampling sites were different from those in the uncontaminated samples. Especially, the relative abundances of and were higher while was lower in the contaminated group than uncontaminated group. Further, potential indicator species, related to Cr such as Cr-remediation genera (, and ); the Cr-sensitive genera (, and ) were also identified. These data revealed that Cr shifted microbial composition and function. Further, Cr (VI) reducing ability could be related with the expression of Cr remediation genes.
黄河是中国北方最重要的水资源。近年来，由于工业生产过程和其他人为活动，重金属污染日益严重。在本研究中，沿着黄河甘肃工业段采集了不同铬（Cr）污染程度的河岸土壤样本，包括未受污染站点（XC、XGU）、轻度污染站点（LJX、XGD）和重度污染站点（CG、XG）的样本。这些样本中的铬浓度从83.83毫克·千克（XGU）到506.58毫克·千克（XG）不等。本研究采集的土壤中铬酸盐[Cr（VI）]还原能力遵循重度污染>轻度污染>未受污染的顺序。在XG和CG样本中检测到常见的Cr修复基因。qRT-PCR结果表明，在XG和CG样本中，[具体基因1]的表达分别上调了4倍和3倍，而在用Cr（VI）处理30分钟后，相同样本中[具体基因2]的表达分别上调了66倍和7倍。在用Cr（VI）培养35天后，[具体基因1]和[具体基因2]的拷贝数没有变化。铬污染采样点的微生物群落与未受污染样本的不同。特别是，污染组中[具体微生物1]和[具体微生物2]的相对丰度较高，而[具体微生物3]的相对丰度低于未污染组。此外，还鉴定出了与铬相关的潜在指示物种，如铬修复属（[具体属1]、[具体属2]和[具体属3]）；铬敏感属（[具体属4]、[具体属5]和[具体属6]）。这些数据表明铬改变了微生物的组成和功能。此外，Cr（VI）还原能力可能与Cr修复基因的表达有关。
