Microbial community structure with trends in methylation gene diversity and abundance in mercury-contaminated rice paddy soils in Guizhou, China

Tatiana A. Vishnivetskaya, Haiyan Hu, Joy D. Van Nostrand, Ann M. Wymore, Xiaohang Xu, Guangle Qiu, Xinbin Feng, Jizhong Zhou, Steven D. Brown, Craig C. Brandt, Mircea Podar, Baohua Gu, Dwayne A. Elias

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Paddy soils from mercury (Hg)-contaminated rice fields in Guizhou, China were studied with respect to total mercury (THg) and methylmercury (MeHg) concentrations as well as Bacterial and Archaeal community composition. Total Hg (0.25-990 μg g-1) and MeHg (1.3-30.5 ng g-1) varied between samples. Pyrosequencing (454 FLX) of the hypervariable v1-v3 regions of the 16S rRNA genes showed that Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, Euryarchaeota, and Crenarchaeota were dominant in all samples. The Bacterial α-diversity was higher in samples with relatively Low THg and MeHg and decreased with increasing THg and MeHg concentrations. In contrast, Archaeal α-diversity increased with increasing of MeHg concentrations but did not correlate with changes in THg concentrations. Overall, the methylation gene hgcAB copy number increased with both increasing THg and MeHg concentrations. The microbial communities at High THg and High MeHg appear to be adapted by species that are both Hg resistant and carry hgcAB genes for MeHg production. The relatively high abundance of both sulfate-reducing δ-Proteobacteria and methanogenic Archaea, as well as their positive correlations with increasing THg and MeHg concentrations, suggests that these microorganisms are the primary Hg-methylators in the rice paddy soils in Guizhou, China.

Original languageEnglish
Pages (from-to)673-685
Number of pages13
JournalEnvironmental Science: Processes and Impacts
Volume20
Issue number4
DOIs
StatePublished - Apr 2018

Funding

† This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, We thank Zamin Yang for help with 454 FLX pyrosequencing and Xiangping Yin for geochemistry analyses. This research was sponsored in part by the Office of Biological and Environmental Research, Office of Science, US Department of Energy (DOE) as part of the Mercury Science Focus Area at Oak Ridge National Laboratory, which is managed by UT-Battelle LLC for the DOE under contract DE-AC05-00OR22725. HH, XX, GQ, and XF were supported by National Natural Science Foundation of China under grant 41303098.

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