Iron‐ and aluminium‐induced depletion of molybdenum in acidic environments impedes the nitrogen cycle

Ge, Xiaoxuan; Vaccaro, Brian J.; Thorgersen, Michael P.; Poole, Farris L.; Majumder, Erica L.-W.; Zane, Grant M.; León, Kara B. De; Lancaster, W. Andrew; Moon, Ji Won; Paradis, Charles; Netzer, Frederick von; Stahl, David A.; Adams, Paul D.; Arkin, Adam P.; Wall, Judy D.; Hazen, Terry C.; Adams, Michael W. W.

doi:10.1111/1462-2920.14435

Cited by 29 publications

(33 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was also evidenced by the notable deposition of extremely insoluble Fe/Mn oxides in the hydragric horizon of Fe-accumuli type, which imparted a reddish color to the soil [39] . Besides, the acidic condition (pH 5.34 ± 0.49) of Fe-accumuli type might also facilitate Fe activity and availability by Fe reduction [40] . By contrast, weak vertical migration of Fe oxides is one typical feature for Hapli-stagnic anthrosol which undergoes relative short-term rice planting period [12,35] .…”

Section: Discussionmentioning

confidence: 99%

“…Mo de ciencymediated suppression in N 2 -xation capacity is a prevalent phenomenon in farmland soils, with a threshold of 0.15 mg kg − 1 for available Mo concentration [44] . In acidic Fe-accumuli soils, it is prone to form recalcitrant Mo induced by Fe-and aluminium precipitation [24,40] . As compared with Hapli-type soil, the lower level in available Mo content of Fe-accumuli soils (0.02 ± 0.01 mg kg − 1 ; Table S1) might also limit nitrogenase activity and thereby impede Mo-dependent N cycle.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Multiple role of diazotrophs in coupling nitrogen and iron biogeochemical processes through vertical soil profiles of different paddy soil types

Wang¹,

Teng²,

Ren³

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: Soil microbiota exert fundamental functions in maintaining ecosystem functioning and services, including pedogenesis, biogeochemical processes and plant productivity, especially for agriculture system. Despite their ubiquitousness from the epipedon to deep soil, the vertical characteristics of microbiomes (especially for functional microorganisms) and their contribution to soil element cycling when considering soil developmental features are poorly understood. Here, nine profiles (0~135 cm) of two canonical paddy soil types (Fe-accumuli- and Hapli-stagnic anthrosols; 111 samples in total) at a local scale were collected, which represented relative long- and short-term water flooding history, respectively. The vertical variations in edaphic characteristics and assemblies of soil bacterial and diazotrophic communities, and microbial contribution to element cycling were explored. Results: Across soil profiles, Hapli-stagnic anthrosol was characteristic of higher concentrations in free iron oxides and total iron in the epipedon, and contained higher amounts of ammonia along the subsurface layers, as compared with acidic Fe-accumuli-anthrosol. Community assemblies of bacteria and diazotrophs, as well as edaphic properties, were mainly shaped by soil depths, followed by soil types. Furthermore, random forest analysis revealed that, for Fe-accumuli-anthrosol, available Fe could best predict nitrogen cycling index and nitrogen status was significantly related to iron cycling index; while in Hapli-stagnic anthrosol, available sulfur was the most important variable in predicting nitrogen and iron cycling indices. Among the dominant genera, some distinctive biomarkers that varied remarkably between the two soil types were noticeable for their contributions to both nitrogen and iron transformation, including iron-reducing diazotroph Geobacter and iron-oxidizing bacterium Rhodanobacter that characterized Fe-accumuli type, and sulfur reducing diazotroph Desulfobacca as main discriminant clades for Hapli-stagnic type.Conclusions: A novel perspective was proposed on the vertical characteristics of edaphic properties and bacterial and diazotrophic communities in the two paddy soil types. The findings indicated the nitrogen-iron cycling processes for Fe-accumuli-anthrosol and nitrogen-iron-sulfur coupling interaction for Hapli-stagnic anthrosol, advancing our understanding of the significant multiple role played by soil microorganisms, especially for diazotrophs, in element biogeochemical cycles.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Multiple role of diazotrophs in coupling nitrogen and iron biogeochemical processes through vertical soil profiles of different paddy soil types

Wang¹,

Teng²,

Ren³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…The Oak Ridge Field Research Center (ORFRC) (10-13) is a well-studied United States Department of Energy site that includes both areas with and without metal contamination, referred to as the contaminated and background sites, respectively. In a recent report (14) the plasmidome of the background site revealed the presence of a highly-abundant native plasmid containing putative mercury resistance genes ( mer ), despite a lack of detectable mercury contamination in the groundwater.…”

Section: Introductionmentioning

confidence: 99%

Native plasmid-encoded mercury resistance genes are functional and demonstrate natural transformation in environmental bacterial isolates

Kothari¹,

Soneja²,

Tang³

et al. 2019

Preprint

View full text Add to dashboard Cite

Plasmid-mediated horizontal gene transfer (HGT) is a major driver of genetic diversity in bacteria. We experimentally validated the function of a putative mercury resistance operon present on an abundant 8 kilobase pair native plasmid found in groundwater samples without detectable levels of mercury. Phylogenetic analyses of the plasmid-encoded mercury reductases from the studied groundwater site show them to be distinct from those reported in proximal metal-contaminated sites. We synthesized the entire native plasmid and demonstrated that the plasmid was sufficient to confer functional mercury resistance in Escherichia coli. Given the possibility that natural transformation is a prevalent HGT mechanism in the low cell density environments of groundwaters, we also assayed bacterial strains from this environment for competence. We used the native plasmid-encoded metal resistance to design a screen and identified 17 strains positive for natural transformation. We selected 2 of the positive strains along with a model bacterium to fully confirm HGT via natural transformation. From an ecological perspective, the role of the native plasmid population in providing advantageous traits combined with the microbiome’s capacity to take up environmental DNA enables rapid adaptation to environmental stresses.ImportanceHorizontal transfer of mobile genetic elements via natural transformation has been poorly understood in environmental microbes. Here, we confirm the functionality of a native plasmid-encoded mercury resistance operon in a model microbe and then query for the dissemination of this resistance trait via natural transformation into environmental bacterial isolates. We identify seventeen strains including Gram-positive and Gram-negative bacteria to be naturally competent. These strains were able to successfully take up the plasmid DNA and obtain a clear growth advantage in the presence of mercury. Our study provides important insights into gene dissemination via natural transformation enabling rapid adaptation to dynamic stresses in groundwater environments.

show abstract

“…Mo availability also influences nitrate reduction in soils. Indeed, at the ORR nitrate-contaminated site, Mo is present at only picomolar concentrations in some of the most highly contaminated groundwater samples in spite of the high concentrations of a variety of other metals (12,21). It was proposed that high concentrations of soluble Fe and Al in the contaminated environment form precipitates as the acidic contaminated groundwater mixes with the surrounding soil.…”

mentioning

confidence: 99%

“…It was proposed that high concentrations of soluble Fe and Al in the contaminated environment form precipitates as the acidic contaminated groundwater mixes with the surrounding soil. These precipitates incorporate and adsorb molybdate, the soluble form of Mo, making it unavailable to microorganisms for nitrate reduction (21).…”

mentioning

confidence: 99%

Nitrate-Utilizing Microorganisms Resistant to Multiple Metals from the Heavily Contaminated Oak Ridge Reservation

Thorgersen

Poole

et al. 2019

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

Contamination of environments with nitrate generated by industrial processes and the use of nitrogen-containing fertilizers is a growing problem worldwide. While nitrate can be removed from contaminated areas by microbial denitrification, nitrate frequently occurs with other contaminants, such as heavy metals, that have the potential to impede the process. Here, nitrate-reducing microorganisms were enriched and isolated from both groundwater and sediments at the Oak Ridge Reservation (ORR) using concentrations of nitrate and metals (Al, Mn, Fe, Co, Ni, Cu, Cd, and U) similar to those observed in a contaminated environment at ORR. Seven new metal-resistant, nitrate-reducing strains were characterized, and their distribution across both noncontaminated and contaminated areas at ORR was examined. While the seven strains have various pH ranges for growth, carbon source preferences, and degrees of resistance to individual and combinations of metals, all were able to reduce nitrate at similar rates both in the presence and absence of the mixture of metals found in the contaminated ORR environment. Four strains were identified in groundwater samples at different ORR locations by exact 16S RNA sequence variant analysis, and all four were found in both noncontaminated and contaminated areas. By using environmentally relevant metal concentrations, we successfully isolated multiple organisms from both ORR noncontaminated and contaminated environments that are capable of reducing nitrate in the presence of extreme mixed-metal contamination. IMPORTANCE Nitrate contamination is a global issue that affects groundwater quality. In some cases, cocontamination of groundwater with nitrate and mixtures of heavy metals could decrease microbially mediated nitrate removal, thereby increasing the duration of nitrate contamination. Here, we used metal and nitrate concentrations that are present in a contaminated site at the Oak Ridge Reservation to isolate seven metal-resistant strains. All were able to reduce nitrate in the presence of high concentrations of a mixture of heavy metals. Four of seven strains were located in pristine as well as contaminated sites at the Oak Ridge Reservation. Further study of these nitrate-reducing strains will uncover mechanisms of resistance to multiple metals that will increase our understanding of the effect of nitrate and metal contamination on groundwater microbial communities.

show abstract

Iron‐ and aluminium‐induced depletion of molybdenum in acidic environments impedes the nitrogen cycle

Cited by 29 publications

References 61 publications

Multiple role of diazotrophs in coupling nitrogen and iron biogeochemical processes through vertical soil profiles of different paddy soil types

Multiple role of diazotrophs in coupling nitrogen and iron biogeochemical processes through vertical soil profiles of different paddy soil types

Native plasmid-encoded mercury resistance genes are functional and demonstrate natural transformation in environmental bacterial isolates

Nitrate-Utilizing Microorganisms Resistant to Multiple Metals from the Heavily Contaminated Oak Ridge Reservation

Contact Info

Product

Resources

About