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Guo P, Du H, Mao Q, Deng Y, Wang X, Li J, Xiong B, Fan X, Wang D, Agathokleous E, Ma M. The duality of sulfate-reducing bacteria: Reducing methylmercury production in rhizosphere but enhancing accumulation in rice plants. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:135049. [PMID: 38970973 DOI: 10.1016/j.jhazmat.2024.135049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/08/2024]
Abstract
Sulfate-reducing bacteria (SRB) are known to alter methylmercury (MeHg) production in paddy soil, but the effect of SRB on MeHg dynamics in rhizosphere and rice plants remains to be fully elucidated. The present study investigated the impact of SRB on MeHg levels in unsterilized and γ-sterilized mercury-polluted paddy soils, with the aim to close this knowledge gap. Results showed that the presence of SRB reduced MeHg production by ∼22 % and ∼17 % in the two soils, but elevated MeHg contents by approximately 55 % and 99 % in rice grains, respectively. Similar trend at smaller scales were seen in roots and shoots. SRB inoculation exerted the most profound impact on amino acid metabolism in roots, with the relative response of L-arginine positively linking to MeHg concentrations in rhizosphere. The SRB-induced enrichment of MeHg in rice plants may be interpreted by the stronger presence of endophytic nitrogen-related microbes (e.g. Methylocaldum, Hyphomicrobium and Methylocystis) and TGA transcription factors interacting with glutathione metabolism and calmodulin. Our study provides valuable insights into the complex effects of SRB inoculation on MeHg dynamics in rice ecosystems, and may help to develop strategies to effectively control MeHg accumulation in rice grains.
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Affiliation(s)
- Pan Guo
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Hongxia Du
- Chongqing Key Laboratory for Innovative Application of Genetic Technology, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Qiaozhi Mao
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Yuhan Deng
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing 400715, PR China
| | - Xun Wang
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Jing Li
- School of Chemical and Pharmaceutical Engineering, Chongqing Industry Polytechnic College, Chongqing 401120, PR China
| | - Bingcai Xiong
- Chongqing Key Laboratory for Innovative Application of Genetic Technology, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Xu Fan
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Dingyong Wang
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing 400715, PR China
| | - Evgenios Agathokleous
- Department of Ecology, School of Ecology and Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, PR China
| | - Ming Ma
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing 400715, PR China.
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Boie F, Ducey TF, Xing Y, Wang J, Rinklebe J. Field-aged rice hull biochar stimulated the methylation of mercury and altered the microbial community in a paddy soil under controlled redox condition changes. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134446. [PMID: 38696958 DOI: 10.1016/j.jhazmat.2024.134446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/25/2024] [Accepted: 04/25/2024] [Indexed: 05/04/2024]
Abstract
Mercury (Hg) contaminated paddy soils are hot spots for methylmercury (MeHg) which can enter the food chain via rice plants causing high risks for human health. Biochar can immobilize Hg and reduce plant uptake of MeHg. However, the effects of biochar on the microbial community and Hg (de)methylation under dynamic redox conditions in paddy soils are unclear. Therefore, we determined the microbial community in an Hg contaminated paddy soil non-treated and treated with rice hull biochar under controlled redox conditions (< 0 mV to 600 mV) using a biogeochemical microcosm system. Hg methylation exceeded demethylation in the biochar-treated soil. The aromatic hydrocarbon degraders Phenylobacterium and Novosphingobium provided electron donors stimulating Hg methylation. MeHg demethylation exceeded methylation in the non-treated soil and was associated with lower available organic matter. Actinobacteria were involved in MeHg demethylation and interlinked with nitrifying bacteria and nitrogen-fixing genus Hyphomicrobium. Microbial assemblages seem more important than single species in Hg transformation. For future directions, the demethylation potential of Hyphomicrobium assemblages and other nitrogen-fixing bacteria should be elucidated. Additionally, different organic matter inputs on paddy soils under constant and dynamic redox conditions could unravel the relationship between Hg (de)methylation, microbial carbon utilization and nitrogen cycling.
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Affiliation(s)
- Felizitas Boie
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany
| | - Thomas F Ducey
- US Department of Agriculture, Coastal Plains Soil, Water, Plant Research Center, 2611 West Lucas Street, Florence, SC, USA
| | - Ying Xing
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; School of Chemistry and Materials Science, Guizhou Normal University, Guiyang 550002, PR China
| | - Jianxu Wang
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 550082 Guiyang, P.R. China
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany.
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Guo P, Du H, Zhao W, Xiong B, Wang M, He M, Flemetakis E, Hänsch R, Ma M, Rennenberg H, Wang D. Selenium- and chitosan-modified biochars reduce methylmercury contents in rice seeds with recruiting Bacillus to inhibit methylmercury production. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133236. [PMID: 38141298 DOI: 10.1016/j.jhazmat.2023.133236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/13/2023] [Accepted: 12/10/2023] [Indexed: 12/25/2023]
Abstract
Biochar could reshape microbial communities, thereby altering methylmercury (MeHg) concentrations in rice rhizosphere and seeds. However, it remains unclear whether and how biochar amendment perturbs microbe-mediated MeHg production in mercury (Hg) contaminated paddy soil. Here, we used pinecone-derived biochar and its six modified biochars to reveal the disturbance. Results showed that selenium- and chitosan-modified biochar significantly reduced MeHg concentrations in the rhizosphere by 85.83% and 63.90%, thereby decreasing MeHg contents in seeds by 86.37% and 75.50%. The two modified bicohars increased the abundance of putative Hg-resistant microorganisms Bacillus, the dominant microbe in rhizosphere. These reductions about MeHg could be facilitated by biochar sensitive microbes such as Oxalobacteraceae and Subgroup_7. Pinecone-derived biochar increased MeHg concentration in rhizosphere but unimpacted MeHg content in seeds was observed. This biochar decreased the abundance in Bacillus but enhanced in putative Hg methylator Desulfovibrio. The increasing MeHg concentration in rhizosphere could be improved by biochar sensitive microbes such as Saccharimonadales and Clostridia. Network analysis showed that Saccharimonadales and Clostridia were the most prominent keystone taxa in rhizosphere, and the three biochars manipulated abundances of the microbes related to MeHg production in rhizosphere by those biochar sensitive microbes. Therefore, selenium- and chitosan-modified biochar could reduce soil MeHg production by these microorganisms, and is helpful in controlling MeHg contamination in rice.
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Affiliation(s)
- Pan Guo
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Hongxia Du
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Wancang Zhao
- Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing 400715, PR China
| | - Bingcai Xiong
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Mingxing Wang
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing 400715, PR China
| | - Mingyan He
- Chongqing Ecological Environment Monitoring Center, Chongqing 401147, PR China
| | - Emmanouil Flemetakis
- Laboratory of Molecular Biology, Department of Biotechnology, Agricultural University of Athens, 11855 Athens, Greece
| | - Robert Hänsch
- Institute for Plant Biology, Technische Universität Braunschweig, Humboldtstraße 1, D-38106, Braunschweig, Germany
| | - Ming Ma
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, PR China.
| | - Heinz Rennenberg
- Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Dingyong Wang
- Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Chongqing 400715, PR China
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Barathi S, Lee J, Venkatesan R, Vetcher AA. Current Status of Biotechnological Approaches to Enhance the Phytoremediation of Heavy Metals in India-A Review. PLANTS (BASEL, SWITZERLAND) 2023; 12:3816. [PMID: 38005713 PMCID: PMC10675783 DOI: 10.3390/plants12223816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023]
Abstract
Rising waste construction, agricultural actions, and manufacturing sewages all contribute to heavy metal accumulation in water resources. Humans consume heavy metals-contaminated substances to make sustenance, which equally ends up in the food circle. Cleaning of these vital properties, along with the prevention of new pollution, has long been required to evade negative strength consequences. Most wastewater treatment techniques are widely acknowledged to be costly and out of the grasp of governments and small pollution mitigation businesses. Utilizing hyper-accumulator plants that are extremely resilient to heavy metals in the environment/soil, phytoremediation is a practical and promising method for eliminating heavy metals from contaminated environments. This method extracts, degrades, or detoxifies harmful metals using green plants. The three phytoremediation techniques of phytostabilization, phytoextraction, and phytovolatilization have been used extensively for soil remediation. Regarding their ability to be used on a wide scale, conventional phytoremediation methods have significant limitations. Hence, biotechnological attempts to change plants for heavy metal phytoremediation methods are extensively investigated in order to increase plant effectiveness and possible use of improved phytoremediation approaches in the country of India. This review focuses on the advances and significance of phytoremediation accompanied by the removal of various harmful heavy metal contaminants. Similarly, sources, heavy metals status in India, impacts on nature and human health, and variables influencing the phytoremediation of heavy metals have all been covered.
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Affiliation(s)
- Selvaraj Barathi
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea; (J.L.); (R.V.)
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea; (J.L.); (R.V.)
| | - Raja Venkatesan
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea; (J.L.); (R.V.)
| | - Alexandre A. Vetcher
- Institute of Biochemical Technology and Nanotechnology, Peoples’ Friendship University of Russia (RUDN), 6 Miklukho-Maklaya St., 117198 Moscow, Russia;
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