Effects of Sulfate Application on Inhibiting Accumulation and Alleviating Toxicity of Arsenic in Panax notoginseng Grown in Arsenic-Polluted Soil

Zeng, Xiancai; Jiang, Yanxue; Fan, Xiaoran; Chao, Sihong; Yue, Yang; Liu, Jianwei; Zhu, Meilin; Cao, Hongbin

doi:10.1007/s11270-016-2836-9

Cited by 8 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26 However, routine hot acid digestion of rice grains leads to transformation of DMMTA to DMA and therefore underestimation of a highly toxic species which is not regulated by the current As rice grain standards. 25 Based on the observed spontaneous thiolation of methylated oxyarsenates, it is to be expected that agronomic practices that have a potential to increase As methylation, such as the soil incorporation of crop residues 8 and sulfate-based fertilization, 48 may also increase the exposure of rice plants to DMMTA.…”

Section: ■ Discussionmentioning

confidence: 99%

Redox Dependence of Thioarsenate Occurrence in Paddy Soils and the Rice Rhizosphere

Wang

Halder

Wegner

et al. 2020

Environ. Sci. Technol.

View full text Add to dashboard Cite

In flooded paddy soils, inorganic and methylated thioarsenates contribute substantially to arsenic speciation besides the much-betterinvestigated oxyarsenic species, and thioarsenate uptake into rice plants has recently been shown. To better understand their fate when soil redox conditions change, that is, from flooding to drainage to reflooding, batch incubations and unplanted microcosm experiments were conducted with two paddy soils covering redox potentials from E H −260 to +200 mV. Further, occurrence of thioarsenates in the oxygenated rice rhizosphere was investigated using planted rhizobox experiments. Soil flooding resulted in rapid formation of inorganic thioarsenates with a dominance of trithioarsenate. Maximum thiolation of inorganic oxyarsenic species was 57% at E H −130 mV and oxidation caused nearly complete dethiolation. Only monothioarsenate formed again upon reflooding and was the major inorganic thioarsenate detected in the rhizosphere. Maximum thiolation of mono-and dimethylated oxyarsenates was about 70% and 100%, respectively, below E H 0 mV. Dithiolated species dominated over monothiolated species below E H −100 mV. Among all thioarsenates, dimethylated monothioarsenate showed the least transformation upon prolonged oxidation. It also was the major thiolated arsenic species in the rhizosphere with concentrations comparable to its precursor dimethylated oxyarsenate, which is especially critical since dimethylated monothioarsenate is highly carcinogenic.

show abstract

Section: ■ Discussionmentioning

confidence: 99%

Redox Dependence of Thioarsenate Occurrence in Paddy Soils and the Rice Rhizosphere

Wang

Halder

Wegner

et al. 2020

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Bright et al showed that sulfate-reducing as well as fermentative and/or methanogenic cultures enriched from lake sediments produced more methylated arsenic than iron- or manganese-reducing cultures. Mikutta and Rothwell showed that 82% of the As in a sulfate- and As-impacted peat bog was present as organoarsenic species, and Zeng et al showed that the abundance of methylated As in the roots of a ginseng plant increased 263% following soil amendment with sulfate (SO 4 2– ). These studies collectively suggest that sulfur and/or sulfate reduction stimulates the biotransformation of As into methylated products, and this hypothesis is supported by functional gene array studies documenting abundant arsM sequences from SRB in soils from Asia, the U.K., and the U.S. , If true, this active role for SRB in arsenic methylation would parallel the well-documented role of SRB as key methylators of mercury in aquatic environments. − Links between SRB and arsenic methylation have not, to our knowledge, been rigorously tested.…”

Section: Introductionmentioning

confidence: 98%

“…Bright et al 30 showed that sulfatereducing as well as fermentative and/or methanogenic cultures enriched from lake sediments produced more methylated arsenic than iron-or manganese-reducing cultures. Mikutta and Rothwell 31 showed that 82% of the As in a sulfate-and Asimpacted peat bog was present as organoarsenic species, and Zeng et al 32 showed that the abundance of methylated As in the roots of a ginseng plant increased 263% following soil amendment with sulfate (SO 4 …”

Section: ■ Introductionmentioning

confidence: 99%

Arsenic Methylation Dynamics in a Rice Paddy Soil Anaerobic Enrichment Culture

Reid

Maillard

Bagnoud

et al. 2017

Environ. Sci. Technol.

View full text Add to dashboard Cite

Methylated arsenic (As) species represent a significant fraction of the As accumulating in rice grains, and there are geographic patterns in the abundance of methylated arsenic in rice that are not understood. The microorganisms driving As biomethylation in paddy environments, and thus the soil conditions conducive to the accumulation of methylated arsenic, are unknown. We tested the hypothesis that sulfate-reducing bacteria (SRB) are key drivers of arsenic methylation in metabolically versatile mixed anaerobic enrichments from a Mekong Delta paddy soil. We used molybdate and monofluorophosphate as inhibitors of sulfate reduction to evaluate the contribution of SRB to arsenic biomethylation, and developed degenerate primers for the amplification of arsM genes to identify methylating organisms. Enrichment cultures converted 63% of arsenite into methylated products, with dimethylarsinic acid as the major product. While molybdate inhibited As biomethylation, this effect was unrelated to its inhibition of sulfate reduction and instead inhibited the methylation pathway. Based on arsM sequences and the physiological response of cultures to media conditions, we propose that amino acid fermenting organisms are potential drivers of As methylation in the enrichments. The lack of a demethylating capacity may have contributed to the robust methylation efficiencies in this mixed culture.

show abstract

“…Other studies have reported an increase in As methylation efficiency after the amendment of sulphate [79] or organic matter to soil [15,[80][81][82], or after the increase in dissolved organic carbon in soil [83]. The positive impact of sulphate amendment on As methylation was interpreted as pointing to the role of SRB in As methylation [79].…”

Section: Discussionmentioning

confidence: 97%

Meta-omics-aided isolation of an elusive anaerobic arsenic-methylating soil bacterium

Viacava

Qiao

Janowczyk

et al. 2022

Preprint

View full text Add to dashboard Cite

Soil microbiomes harbour unparalleled functional and phylogenetic diversity. However, extracting isolates with a targeted function from complex microbiomes is not straightforward, particularly if the associated phenotype does not lend itself to high-throughput screening. Here, we tackle the methylation of arsenic (As) in anoxic soils. As methylation was proposed to be catalysed by sulphate-reducing bacteria. However, to date, there are no available anaerobic isolates capable of As methylation, whether sulphate-reducing or otherwise. The isolation of such a microorganism has been thwarted by the fact that the anaerobic bacteria harbouring a functional arsenite S-adenosylmethionine methyltransferase (ArsM) tested to date did not methylate As in pure culture. Additionally, fortuitous As methylation can result from the release of non-specific methyltransferases upon lysis. Thus, we combined metagenomics, metatranscriptomics, and metaproteomics to identify the microorganisms actively methylating As in anoxic soil-derived microbial cultures. Based on the metagenome-assembled genomes of microorganisms expressing ArsM, we isolated Paraclostridium sp. strain EML, which was confirmed to actively methylate As anaerobically. This work is an example of the application of meta-omics to the isolation of elusive microorganisms.

show abstract

Effects of Sulfate Application on Inhibiting Accumulation and Alleviating Toxicity of Arsenic in Panax notoginseng Grown in Arsenic-Polluted Soil

Cited by 8 publications

References 47 publications

Redox Dependence of Thioarsenate Occurrence in Paddy Soils and the Rice Rhizosphere

Redox Dependence of Thioarsenate Occurrence in Paddy Soils and the Rice Rhizosphere

Arsenic Methylation Dynamics in a Rice Paddy Soil Anaerobic Enrichment Culture

Meta-omics-aided isolation of an elusive anaerobic arsenic-methylating soil bacterium

Contact Info

Product

Resources

About