scholarly journals High arsenic levels increase activity rather than diversity or abundance of arsenic metabolism genes in paddy soils

2021 ◽  
Author(s):  
Si-Yu Zhang ◽  
Xiao Xiao ◽  
Song-Can Chen ◽  
Yong-Guan Zhu ◽  
Guo-Xin Sun ◽  
...  
Keyword(s):  
Transcriptional Activity ◽  
Agricultural Soils ◽  
Geographic Distance ◽  
Environmental Pollutant ◽  
Paddy Soils ◽  
As Species ◽  
Toxic Metalloid ◽  
High Concentrations ◽  
Abundance And Diversity ◽  
Transcriptome Level

Arsenic (As) metabolism genes are generally present in soils but their diversity, relative abundance, and transcriptional activity in response to different As concentrations remain unclear, limiting our understanding of the microbial activities that control the fate of an important environmental pollutant. To address this issue, we applied metagenomics and metatranscriptomics to paddy soils showing a gradient of As concentrations to investigate As resistance genes ( ars ) including arsR , acr3 , arsB , arsC , arsM , arsI , arsP , and arsH as well as energy-generating As respiratory oxidation ( aioA ) and reduction ( arrA ) genes. Somewhat unexpectedly, the relative DNA abundances and diversity of ars , aioA , and arrA genes were not significantly different between low and high (∼10 vs ∼100 mg kg −1 ) As soils. By comparison to available metagenomes from other soils, geographic distance rather than As levels drove the different compositions of microbial communities. Arsenic significantly increased ars genes abundance only when its concentration was higher than 410 mg kg −1 . In contrast, between low and high As soils, metatranscriptomics revealed a significant increase in transcription of ars and aioA genes, which are induced by arsenite, the dominant As species in paddy soils, but not arrA genes, which are induced by arsenate. These patterns appeared to be community-wide as opposed to taxon-specific. Collectively, our findings advance understanding of how microbes respond to high As levels and the diversity of As metabolism genes in paddy soils and indicated that future studies of As metabolism in soil, or other environments, should include the function (transcriptome) level. IMPORTANCE Arsenic (As) is a toxic metalloid pervasively present in the environment. Microorganisms have evolved the capacity to metabolize As, and As metabolism genes are ubiquitously present in the environment even in the absence of high concentrations of As. However, these previous studies were carried out at the DNA level and thus, the activity of the As metabolism genes detected remains essentially speculative. Here, we show that the high As levels in paddy soils increased the transcriptional activity rather than the relative DNA abundance and diversity of As metabolism genes. These findings advance our understanding of how microbes respond to and cope with high As levels and have implications for better monitoring and managing an important toxic metalloid in agricultural soils and possibly other ecosystems.

scholarly journals High arsenic levels increase activity rather than diversity or abundance of arsenic metabolism genes in paddy soils

2021 ◽  
Author(s):  
Si-Yu Zhang ◽  
Xiao Xiao ◽  
Song-Can Chen ◽  
Yong-Guan Zhu ◽  
Konstantinos T. Konstantinidis
Keyword(s):  
Transcriptional Activity ◽  
Agricultural Soils ◽  
Geographic Distance ◽  
Environmental Pollutant ◽  
Paddy Soils ◽  
As Species ◽  
Toxic Metalloid ◽  
High Concentrations ◽  
Abundance And Diversity ◽  
Transcriptome Level

Abstract Arsenic (As) metabolism genes are generally present in soils but their diversity, relative abundance, and transcriptional activity in response to different As concentrations remain unclear, limiting our understanding of the microbial activities that control the fate of an important environmental pollutant. To address this issue, we applied metagenomics and metatranscriptomics to paddy soils showing a gradient of As concentrations to investigate As resistance genes (ars) including arsR, acr3, arsB, arsC, arsM, arsI, arsP, and arsH as well as energy-generating As respiratory oxidation (aioA) and reduction (arrA) genes. Somewhat unexpectedly, the relative DNA abundances and diversity of ars, aioA, and arrA genes were not significantly different between low and high (~10 vs ~100 mg kg-1) As soils. By comparison to available metagenomes from other soils, geographic distance rather than As levels drove the different compositions of microbial communities. Arsenic significantly increased ars genes abundance only when its concentration was higher than 410 mg kg-1. In contrast, between low and high As soils, metatranscriptomics revealed a significant increase in transcription of ars and aioA genes, which are induced by arsenite, the dominant As species in paddy soils, but not arrA genes, which are induced by arsenate. These patterns appeared to be community-wide as opposed to taxon-specific. Collectively, our findings advance understanding of how microbes respond to high As levels and the diversity of As metabolism genes in paddy soils and indicated that future studies of As metabolism in soil, or other environments, should include the function (transcriptome) level. IMPORTANCEArsenic (As) is a toxic metalloid pervasively present in the environment. Microorganisms have evolved the capacity to metabolize As, and As metabolism genes are ubiquitously present in the environment even in the absence of high concentrations of As. However, these previous studies were carried out at the DNA level and thus, the activity of the As metabolism genes detected remains essentially speculative. Here, we show that the high As levels in paddy soils increased the transcriptional activity rather than the relative DNA abundance and diversity of As metabolism genes. These findings advance our understanding of how microbes respond to and cope with high As levels and have implications for better monitoring and managing an important toxic metalloid in agricultural soils and possibly other ecosystems.

scholarly journals High Arsenic Levels Increase Activity Rather Than Diversity or Abundance of Arsenic Metabolism Genes in Paddy Soils

2021 ◽  
Author(s):  
Si-Yu Zhang ◽  
Xiao Xiao ◽  
Song-Can Chen ◽  
Yong-Guan Zhu ◽  
Konstantinos T. Konstantinidis
Keyword(s):  
Geographic Distance ◽  
Environmental Pollutant ◽  
Paddy Soils ◽  
High Concentration ◽  
Future Studies ◽  
As Species ◽  
Toxic Metalloid ◽  
Occurrence Patterns ◽  
Transcriptome Level ◽  
High Arsenic

Abstract BackgroundArsenic (As) is a toxic metalloid pervasively present in the environment. Microorganisms have evolved the capacity to metabolize As, and As metabolism genes are ubiquitously present in the environment even in the absence of high concentration of As. However, the As metabolism genes diversity, relative abundance, and transcriptional activity in response to different As levels remain unclear, limiting our understanding of the microbial activities that control the fate of an important environmental pollutant. To address this issue, we applied metagenomics and metatranscriptomics to paddy soils showing a gradient of As concentrations to investigate As resistance genes (ars), including arsR, acr3, arsB, arsC, arsM, arsI, arsP and arsH as well as energy-generating As respiratory oxidation (aioA) and reduction (arrA) genes.ResultsSomewhat unexpectedly, the relative DNA abundances and diversity of ars, aioA and arrA genes were not significantly different between low and high (~10 vs ~100 mg kg-1) As soils. By comparison to available metagenomes from other soils, geographic distance rather than As levels drove the different composition of microbial communities. Arsenic significantly increased ars genes abundance only when its concentration was higher than 410 mg kg -1. In contrast, between low and high (~10 vs ~100 mg kg-1) As soils, metatranscriptomics revealed a significant increase in transcription of ars and aioA genes, which are induced by arsenite, the dominant As species in paddy soils, but not arrA genes, which are induced by arsenate. Co-occurrence patterns of arsR, acr3, and arsM genes were revealed by network analysis corroborating that the arsR, acr3 and arsM genes are usually organized in a single ars operon. The transcriptome level response appeared to be community-wide as opposed to taxon-specific. ConclusionsHigh As levels increased the activity of As metabolism genes rather than their abundance or diversity in paddy soils. These findings advance understanding of how microbes respond to high As levels and the diversity of As metabolism genes in paddy soils, and indicated that future studies of As metabolism in soil, and likely other environments, should include the function (transcriptome) level.

scholarly journals Benthic assemblages in two Mediterranean caves: species diversity and coverage as a function of abiotic parameters and geographic distance

2004 ◽  
Vol 84 (3) ◽  
pp. 557-572 ◽  
Author(s):  
Ruth Martí ◽  
Maria J. Uriz ◽  
Enric Ballesteros ◽  
Xavier Turon
Keyword(s):  
Water Movement ◽  
Benthic Communities ◽  
Geographic Distance ◽  
Species Abundance ◽  
Geographic Location ◽  
Benthic Assemblages ◽  
Abiotic Parameters ◽  
As Species ◽  
Abundance And Diversity ◽  
Submarine Caves

Benthic assemblages of two Mediterranean submarine caves were compared. Species coverage and number of species were lower in internal (dark) communities than external. This feature was specially marked in the less illuminated cave. Ordination analyses performed on species coverage per community for each cave separately, distinguished several benthic communities from the outermost to the innermost zone of each cave. Cluster analyses on species coverage, taking into account all communities in both the caves, established similarities among communities: algal-dominated communities clustered according to the level of light received independently of the cave they inhabited, while animal-dominated communities were more similar within each cave than between the caves. Moreover, among the abiotic parameters measured irradiance was the only factor that clearly diminished from the entrance to the innermost zone in both the caves. In contrast, water movement and particulate organic matter varied differently in each cave. Results indicate that the different topography, depth and geographic location of the two caves determine water movement, light penetration and nutrient availability along the caves. These factors are responsible for determining species abundance and diversity, as well as species growth habit in each community.

Abundance and Diversity of CO2-Assimilating Bacteria and Algae Within Red Agricultural Soils Are Modulated by Changing Management Practice

2015 ◽  
Vol 70 (4) ◽  
pp. 971-980 ◽  
Author(s):  
Hongzhao Yuan ◽  
Tida Ge ◽  
Xiangbi Chen ◽  
Shoulong Liu ◽  
Zhenke Zhu ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
Management Practice ◽  
Abundance And Diversity

Spatial content and variability of mercury in agricultural soils in the province of Valencia (Spain), with an emphasis on those dedicated to rice crop

2021 ◽  
Author(s):  
Rafael Boluda ◽  
Luis Roca Pérez ◽  
Joaquín Ramos Miras ◽  
José A. Rodríguez Martín ◽  
Jaume Bech Borras
Keyword(s):  
Spatial Distribution ◽  
Rice Straw ◽  
Agricultural Soils ◽  
Simple Random Sampling ◽  
Rice Paddy ◽  
Paddy Soils ◽  
Systematic Sampling ◽  
Rice Paddies ◽  
Natural Park ◽  
Rice Paddy Soils

<p>Mercury (Hg) is a metal potentially dangerous that can accumulate in soils, move to plants and cause significant ecotoxicological risks. The province of Valencia is the third in Spain and has a great agricultural, industrial and tourist vocation; it has an area of 10,763 km<sup>2</sup>, of which it devotes 272,978 ha to cultivation, most of which are irrigated soils. To the south of the city of Valencia, is the Albufera Natural Park (ZEPA area and Ramsar wetland) with 14,806 ha dedicated to rice cultivation. Pollution and burning of rice straw in rice paddies are serious problems. Therefore, the concentration of Hg in agricultural soils in the province of Valencia according to use, with an emphasis on rice paddy soils, and spatial distribution were determined; and the effects of rice straw burning on Hg accumulation on rice paddy soils was assessed. Systematic sampling was carried out throughout the agricultural area at an intensity of a grid of 8 x 8 km, in which samples composed of soil between 0 and 20 cm were collected in a total of 98 plots; and a simple random sampling in the case of rice paddies in 35 sites, distinguishing between plots where the incineration of rice straw was carried out and where it was not. The concentration of Hg was determined with a direct DMA-80 Milestone analyzer in the previously pulverized sample. The detection limit was 1.0 g kg<sup>-1</sup>, the recovery was 95.1% to 101.0% ± 4.0%. The analyses were performed in triplicate. A basic descriptive statistic (means, medians, deviations, and ANOVA) was performed. Samples were grouped according to land use. For geostatistic analysis and in order to obtain the map of the spatial distribution of the concentration of Hg in soils, the classical geostatistic technique was used by ordinary kriging. The concentration of Hg in the soils of the province of Valencia showed great variability. The soils of the rice paddies together with those dedicated to the cultivation of citrus and horticultural of the coastal plain, showed the highest levels of Hg, in contrast to the soils of the interior areas dedicated to dry crops (vineyards, olive, almond and fodder). Spatial analysis reflected a concentration gradient from west to east, suggesting that the Hg in the soils of the interior has a geochemical origin, while in the coast soils it is of anthropic origin. On the other hand, it was observed that the burning of rice straw increased the Hg concentration in rice paddy soils. This research is the first information on the distribution of Hg in the soils of the province of Valencia and a contribution that can help weigh the effects of open burning of rice straw on Valencian rice paddies.</p>

Nonadrenergic bronchodilation induced by high concentrations of sulfur dioxide

1990 ◽  
Vol 69 (5) ◽  
pp. 1786-1791
Author(s):  
D. C. Thompson ◽  
J. L. Szarek ◽  
R. J. Altiere ◽  
L. Diamond
Keyword(s):  
Muscle Tone ◽  
Blocking Agent ◽  
Lung Compliance ◽  
Environmental Pollutant ◽  
Inhibitory System ◽  
Experimental Conditions ◽  
Bronchodilator Response ◽  
Cellular Source ◽  
High Concentrations ◽  
Dynamic Lung Compliance

SO2 is an environmental pollutant known to elicit bronchospasm in susceptible subjects. We observed that brief exposure of artificially bronchoconstricted cats to high concentrations of SO2 induces a bronchodilator response. This study assessed the characteristics of this response and examined various mechanisms that might underlie it. Cats were anesthetized with diallylbarbital-urethan, and airway smooth muscle tone, measured by lung resistance and dynamic lung compliance, was elevated with a continuous infusion of 5-hydroxytryptamine. Administration of 10 breaths of SO2 via a tracheostomy induced concentration-dependent bronchodilation in the range 100-1,000 parts/million. Only infrequently was bronchoconstriction observed before bronchodilation. SO2-induced bronchodilator responses were unaffected by pretreatment with intravenous atropine or propranolol, establishing them as nonadrenergic noncholinergic (NANC) in origin. Neither the ganglionic blocking agent hexamethonium nor the nerve toxin tetrodotoxin influenced the SO2-induced bronchodilation, thus excluding a role for central or local autonomic reflexes in the response. Efforts to modulate the response by pretreatment with the cyclooxygenase inhibitor indomethacin or the mediator release inhibitor cromolyn sodium also were unsuccessful. Administration of acidic aerosols failed to mimic the SO2-induced bronchodilator response. Although the mechanism whereby SO2 induces bronchodilation under these experimental conditions remains unclear, release of a NANC inhibitory transmitter from a neural, epithelial, or other cellular source via a mechanism insensitive to both tetrodotoxin and cromolyn is a distinct possibility. An intrinsic NANC inhibitory system may exist in feline airways functioning as a local regulator of bronchomotor tone and possibly serving to override responses to strong, potentially asphyxial bronchoconstrictive stimuli.

scholarly journals Residues of Persistent Organic Pollutants (POPs) in Agricultural Soils Adjacent to Historical Sources of Their Storage and Distribution—The Case Study of Azerbaijan

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1815 ◽  
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Karolina Lewińska ◽  
Elton Mammadov ◽  
Anna Karczewska ◽  
Bożena Smreczak ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Environmental Protection Agency ◽  
Agricultural Soils ◽  
The United States ◽  
Natural Soil ◽  
Polycyclic Aromatic ◽  
High Concentrations ◽  
Total Concentrations

The aim of this study was to identify and examine the levels of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) in soil collected from the surroundings of historical pesticide storage facilities on former agricultural aerodromes, warehouses, and pesticide distribution sites located in the most important agricultural regions in Azerbaijan. The conducted research included determination of three groups of POPs (occurring together), in the natural soil environment influenced for many years by abiotic and biotic factors that could have caused their transformations or decomposition. In this study, soil samples were collected in 21 georeferenced points located in the administrative area of Bilasuvar, Saatly, Sabirabad, Salyan and Jalilabad districts of Azerbaijan. Soil chemical analysis involved determination of organochlorine compounds (OCP): hexachlorocyclohexanes (HCHs) (three isomers α-HCH, β-HCH and γ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (six congeners 2,4′DDT; 4,4′DDT; 2,4′DDE; 4,4′DDE; 2,4′DDE; and 4,4′DDE); polycyclic aromatic hydrocarbons (PAHs): 16 compounds from the United States Environmental Protection Agency US EPA list and, PCBs (seven congeners identified with the following IUPAC numbers: 28, 52, 101, 118, 138, 153, and 180). Our research showed that OCPs reached the highest concentration in the studied areas. The total concentrations of OCPs ranged from 0.01 to 21,888 mg∙kg−1 with significantly higher concentrations of Σ6DDTs (0.01 μg kg−1 to 21880 mg kg−1) compared to ΣHCH (0.14 ng kg−1 to 166.72 µg kg−1). The total concentrations of PCBs in the studied soils was varied from 0.02 to 147.30 μg·kg−1 but only PCB138 and PCB180 were detected in all analyzed samples. The concentrations of Σ16 PAHs were also strongly diversified throughout the sampling areas and ranged from 0.15 to 16,026 mg kg−1. The obtained results confirmed that the agricultural soils of Azerbaijan contained much lower (up to by three orders of magnitude) concentrations of PCBs and PAHs than DDT. It is supported by the fact that PCBs and PAHs were not directly used by agriculture sector and their content results from secondary sources, such as combustion and various industrial processes. Moreover, the high concentrations of PAHs in studied soils were associated with their location in direct neighborhood of the airport, as well as with accumulation of contaminants from dispersed sources and long range transport. The high concentrations of pesticides confirm that deposition of parent OCPs have occurred from obsolete pesticide landfills.

scholarly journals Heavy Metal Contents of Municipal and Rural Dumpsite Soils and Rate of Accumulation byCarica papayaandTalinum triangularein Uyo, Nigeria

2008 ◽  
Vol 5 (2) ◽  
pp. 281-290 ◽  
Author(s):  
G. A. Ebong ◽  
M. M. Akpan ◽  
V. N. Mkpenie
Keyword(s):  
Fruits And Vegetables ◽  
Agricultural Soils ◽  
Toxic Metal ◽  
The Other ◽  
Plant Parts ◽  
Metal Contents ◽  
Metal Levels ◽  
High Concentrations ◽  
The Impact ◽  
The Relationship

Dumpsites in Uyo and most cities in Nigeria are used nutrients rich soils for cultivating fruits and vegetables without regards to the risk of toxic metal pollution by the wastes. This development necessitated the research on the assessment of the impact of municipal and rural dumpsites on the metal levels of the underlying soils, the relationship between the dumpsite- soil metal content and the rate of bio-accumulation by plants, the effect of plant specie and plant part on the rate of metal uptake. Atomic absorption spectrophotometer was employed for the analysis of the samples and results obtained from municipal dumpsite soil indicated the following mean concentrations: Fe, 1711.20 μg/g; Pb, 43.28 ug/g; Zn, 88.34 ug/g; Ni, 12.18 ug/g; Cd, 14.10 ug/g and Cu, 56.33 ug/g. These concentrations were relatively higher than the following concentrations: Fe, 1016.98 ug/g; Pb, 18.57 ug/g; Zn, 57.90 ug/g; Ni, 7.98 ug/g; Cd, 9.25 ug/g and Cu, 33.70 ug/g recorded for the rural dumpsite soil. Consequently, plants grown on municipal dumpsites soil accumulated higher concentrations of the metals than those on rural dumpsites. Results obtained from this study also revealed that plants grown on dumpsite soils bio-accumulated higher metal concentrations than their counterparts obtained from normal agricultural soils. The ability of plants to bioaccumulate these metals were also observed as being different from one plant to the other and from one plant parts to the other. And apart from Fe and Zn which recorded higher concentrations in the leaves of the plants studied, other metals recorded higher concentrations in the roots. The general results obtained revealed that the levels of Cd in dumpsite-soil were above the standard while the levels of Cd and Pb in plants were also above the recommended levels in plants. The implications of these high concentrations of these metals in soil and plants have been discussed. Some useful recommendations on the proper handling of wastes to reduce toxic metal loads at dumpsites have also been highlighted.

Ecological niche differentiation of ammonia-oxidising archaea and bacteria in acidic soils due to land use change

Soil Research ◽  
2018 ◽  
Vol 56 (1) ◽  
pp. 71 ◽  
Author(s):  
Shenyan Dai ◽  
Qian Liu ◽  
Jun Zhao ◽  
Jinbo Zhang
Keyword(s):  
Land Use ◽  
Ecological Niche ◽  
Ammonia Oxidation ◽  
Agricultural Soils ◽  
Niche Differentiation ◽  
Stable Isotope Probing ◽  
Paddy Soils ◽  
Acidic Soils ◽  
Moisture Condition ◽  
Ammonia Oxidising Archaea

Nitrification can be driven by either ammonia-oxidising bacteria (AOB) or ammonia-oxidising archaea (AOA) and is a central process in the nitrogen cycle. However, to date, it is not clear how the ecological niche differentiation of AOB and AOA are affected by land use and management changes in strongly acidic soils in subtropical China. In this study, three different land-use acidic soils – forest, upland, and paddy soils – were collected and a DNA Stable-Isotope Probing experiment performed to determine the relative contributions of AOA and AOB to ammonia oxidation in these soils. The results showed that AOA, but not AOB, amoA genes were detected in 13C-labelled DNA in the forest and paddy soils; however, only AOB amoA genes were detected in 13C-labelled DNA in the upland agricultural soils. The growth and activity of AOA and AOB in the different land-use soils provided direct evidence for the shift in roles for AOA and AOB in ammonia oxidation. AOA played the predominant role in ammonia oxidation in acidic forest and paddy soils. However, AOB, not AOA, mainly regulated the ammonia oxidation in acidic upland agricultural soils. Phylogenetic analysis indicated that AOA members within the marine Group1.1a-associated lineage dominated nitrification in the forest and paddy soils. Ammonia oxidation in the upland soil was catalysed by Nitrosospira cluster 3-like AOB. The moisture condition was likely the main reason inducing the ecological niche differentiation between upland and paddy soils; and AOA was more suitable for growth in the flooded, low oxygen conditions.

scholarly journals Production and Excretion of Polyamines To Tolerate High Ammonia, a Case Study on Soil Ammonia-Oxidizing Archaeon “Candidatus Nitrosocosmicus agrestis”

mSystems ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Liangting Liu ◽  
Mengfan Liu ◽  
Yiming Jiang ◽  
Weitie Lin ◽  
Jianfei Luo
Keyword(s):  
Agricultural Soils ◽  
Metagenomic Data ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Polyamine Synthesis ◽  
Ammonia Oxidizing Archaea ◽  
High Ammonia ◽  
Genes Encoding ◽  
High Concentrations ◽  
Ammonia Tolerance

ABSTRACT Ammonia tolerance is a universal characteristic among the ammonia-oxidizing bacteria (AOB); in contrast, the known species of ammonia-oxidizing archaea (AOA) have been regarded as ammonia sensitive, until the identification of the genus “Candidatus Nitrosocosmicus.” However, the mechanism of its ammonia tolerance has not been reported. In this study, the AOA species “Candidatus Nitrosocosmicus agrestis,” obtained from agricultural soil, was determined to be able to tolerate high concentrations of NH3 (>1,500 μM). In the genome of this strain, which was recovered from metagenomic data, a full set of genes for the pathways of polysaccharide metabolism, urea hydrolysis, arginine synthesis, and polyamine synthesis was identified. Among them, the genes encoding cytoplasmic carbonic anhydrase (CA) and a potential polyamine transporter (drug/metabolite exporter [DME]) were found to be unique to the genus “Ca. Nitrosocosmicus.” When “Ca. Nitrosocosmicus agrestis” was grown with high levels of ammonia, the genes that participate in CO2/HCO3− conversion, glutamate/glutamine syntheses, arginine synthesis, polyamine synthesis, and polyamine excretion were significantly upregulated, and the polyamines, including putrescine and spermidine, had significant levels of production. Based on genome analysis, gene expression quantification, and polyamine determination, we propose that the production and excretion of polyamines is probably one of the reasons for the ammonia tolerance of “Ca. Nitrosocosmicus agrestis,” and even of the genus “Ca. Nitrosocosmicus.” IMPORTANCE Ammonia tolerance of AOA is usually much lower than that of the AOB, which makes the AOB rather than AOA a predominant ammonia oxidizer in agricultural soils, contributing to global N2O emission. Recently, some AOA species from the genus “Ca. Nitrosocosmicus” were also found to have high ammonia tolerance. However, the reported mechanism for the ammonia tolerance is very rare and indeterminate for AOB and for AOA species. In this study, an ammonia-tolerant AOA strain of the species “Ca. Nitrosocosmicus agrestis” was identified and its potential mechanisms for ammonia tolerance were explored. This study will be of benefit for determining more of the ecological role of AOA in agricultural soils or other environments.

Sign in / Sign up

Export Citation Format

Share Document