Bacterial assemblages imply methylmercury production at the rice-soil system

Pan Guo; Heinz Rennenberg; Hongxia Du; Tao Wang; Lan Gao; Emmanouil Flemetakis; Robert Hänsch; Ming Ma; Dingyong Wang

doi:10.1016/j.envint.2023.108066

Bacterial assemblages imply methylmercury production at the rice-soil system

Environ Int. 2023 Aug:178:108066. doi: 10.1016/j.envint.2023.108066. Epub 2023 Jun 29.

Authors

Pan Guo¹, Heinz Rennenberg¹, Hongxia Du², Tao Wang¹, Lan Gao¹, Emmanouil Flemetakis³, Robert Hänsch⁴, Ming Ma⁵, Dingyong Wang⁶

Affiliations

¹ Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing, China.
² Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing, China.
³ Laboratory of Molecular Biology, Department of Biotechnology, Agricultural University of Athens, 11855 Athens, Greece.
⁴ Institute for Plant Biology, Technische Universität Braunschweig, Humboldtstraße 1, D-38106 Braunschweig, Germany.
⁵ Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing, China; Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing, China. Electronic address: maming@swu.edu.cn.
⁶ Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing, China.

PMID: 37399771
DOI: 10.1016/j.envint.2023.108066

Abstract

The plant microbiota can affect plant health and fitness by promoting methylmercury (MeHg) production in paddy soil. Although most well-known mercury (Hg) methylators are observed in the soil, it remains unclear how rice rhizosphere assemblages alter MeHg production. Here, we used network analyses of microbial diversity to identify bulk soil (BS), rhizosphere (RS) and root bacterial networks during rice development at Hg gradients. Hg gradients greatly impacted the niche-sharing of taxa significantly relating to MeHg/THg, while plant development had little effect. In RS networks, Hg gradients increased the proportion of MeHg-related nodes in total nodes from 37.88% to 45.76%, but plant development enhanced from 48.59% to 50.41%. The module hub and connector in RS networks included taxa positively (Nitrososphaeracea, Vicinamibacteraceae and Oxalobacteraceae) and negatively (Gracilibacteraceae) correlating with MeHg/THg at the blooming stage. In BS networks, Deinococcaceae and Paludibacteraceae were positively related to MeHg/THg, and constituted the connector at the reviving stage and the module hub at the blooming stage. Soil with an Hg concentration of 30 mg kg^-1 increased the complexity and connectivity of root microbial networks, although microbial community structure in roots was less affected by Hg gradients and plant development. As most frequent connector in root microbial networks, Desulfovibrionaceae did not significantly correlate with MeHg/THg, but was likely to play an important role in the response to Hg stress.

Keywords: Mercury gradient; Methylation; Microbial interaction; Plant development; Rice.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacteria
Environmental Monitoring
Mercury* / analysis
Methylmercury Compounds* / analysis
Oryza* / chemistry
Soil / chemistry
Soil Pollutants* / analysis

Substances

Methylmercury Compounds
Soil
Soil Pollutants
Mercury