The influence of Glyceria maxima and nitrate input on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community

Nijburg, J. W.; Laanbroek, Hendrikus J.

doi:10.1111/j.1574-6941.1997.tb00356.x

Cited by 37 publications

(18 citation statements)

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“…Corre and co-workers [13] suggested a high competition for available N between microorganisms and plant. Moreover, Nijburg and co-workers [37,38] noticed that addition of nitrate in the rhizosphere of G. maxima resulted in an increased number of NR strains. In order to test the role of nitrate availability, a similar experiment was conducted on L. perenne grown with low and high (non-limitative) nitrogen supply, during which the role of nitrate availability was confirmed (L. RousselDelif, S. Tarnawski, J. Hamelin, E.M. Baggs, M. Aragno, and N. Fromin, in preparation).…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the ability to use nitrate as alternative electron acceptor could be a competitive advantage for bacteria in the rhizosphere, where oxygen is limiting because of root and microbial respiration [21]. In contrast, Nijburg and co-workers [37,38] reported a lower proportion of nitrate-reducing bacterial isolates in the rhizosphere of the aerenchymatous wetland plant Glyceria maxima compared to nonrhizospheric soil, suggesting that the availability of nitrate is also crucial for nitrate dissimilation. Various studies showed that denitrification in soil is also influenced by soil properties and agricultural practices [9,12,17,40,54].…”

Section: Introductionmentioning

confidence: 99%

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Frequency and Diversity of Nitrate Reductase Genes among Nitrate-Dissimilating Pseudomonas in the Rhizosphere of Perennial Grasses Grown in Field Conditions

et al. 2005

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A total of 1246 Pseudomonas strains were isolated from the rhizosphere of two perennial grasses (Lolium perenne and Molinia coerulea) with different nitrogen requirements. The plants were grown in their native soil under ambient and elevated atmospheric CO 2 content (pCO 2 ) at the Swiss FACE (Free Air CO 2 Enrichment) facility. Root-, rhizosphere-, and non-rhizospheric soil-associated strains were characterized in terms of their ability to reduce nitrate during an in vitro assay and with respect to the genes encoding the membrane-bound (named NAR) and periplasmic (NAP) nitrate reductases so far described in the genus Pseudomonas. The diversity of corresponding genes was assessed by PCR-RFLP on narG and napA genes, which encode the catalytic subunit of nitrate reductases. The frequency of nitrate-dissimilating strains decreased with root proximity for both plants and was enhanced under elevated pCO 2 in the rhizosphere of L. perenne. NAR (54% of strains) as well as NAP (49%) forms were present in nitrate-reducing strains, 15.5% of the 439 strains tested harbouring both genes. The relative proportions of narG and napA detected in Pseudomonas strains were different according to root proximity and for both pCO 2 treatments: the NAR form was more abundant close to the root surface and for plants grown under elevated pCO 2 . Putative denitrifiers harbored mainly the membrane-bound (NAR) form of nitrate reductase. Finally, both narG and napA sequences displayed a high level of diversity. Anyway, this diversity was correlated neither with the root proximity nor with the pCO 2 treatment.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Frequency and Diversity of Nitrate Reductase Genes among Nitrate-Dissimilating Pseudomonas in the Rhizosphere of Perennial Grasses Grown in Field Conditions

et al. 2005

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“…The presence of certain macrophytes in low nitrate sediments may greatly increase the proportion of DNRA to denitrification, possibly due to increased C availability from root exudates and elevated O 2 levels, (Nijburg & Laanbroek 1997b). Aerenchymatous plants release O 2 into the root zone when healthy (Nijburg et al 1997), and this process in turn selects for DNRA over denitrification as DNRA is less inhibited by O 2 presence than denitrification, especially at high C:N ratios (Fazzolari et al 1998). Potamogeton praelongus and Elodea canadensis (identified as aerenchymatous macrophytes) were abundant in Bull Trout Lake and were present at Site 5.…”

Section: Spatial Patterns In No 3 − Losses By Dissimilatory Pathwaysmentioning

confidence: 99%

Dissimilatory nitrate reduction pathways in an oligotrophic freshwater ecosystem: spatial and temporal trends

Washbourne¹,

Crenshaw²,

Baker³

2011

Aquat. Microb. Ecol.

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Elevated nitrate (NO 3 − ) concentrations can cause eutrophication, which may lead to harmful algal blooms, loss of habitat and reduction in biodiversity. Denitrification, a dissimilatory process that removes NO 3 − mainly as dinitrogen gas (N 2 ), is believed to be the dominant NO 3 − removal pathway in aquatic ecosystems. Evidence suggests that a less well-studied process, dissimilatory nitrate reduction to ammonium (DNRA), which retains nitrogen (N) in the system, may also be important under favorable conditions. Using stable isotope tracers in sealed microcosms, we measured the potential for NO 3 − losses due to DNRA and denitrification in an oligotrophic freshwater ecosystem. We took sediment and water samples at runoff and baseflow, across several ecotypes. Our objective was to quantify the relative importance of DNRA compared to denitrification with changes in ecotype and season. Potential denitrification rates ranged from 0 to 0.14 ± 0.03 µgN gAFDM −1 d −1. Potential DNRA rates ranged from 0 to 0.0051 ± 0.0008 µgN gAFDM −1 d −1. Denitrification losses peaked at the inflow stream ecotype at 96.2% of total dissimilatory NO 3 − removal, whereas losses due to DNRA peaked in the lake ecotype at 34.4%. When averaged over the entire system, denitrification peaked at baseflow (31.2%), while DNRA peaked at runoff (2.9%). Although NO 3 − transformations due to denitrification were higher than DNRA in all ecotype and temporal comparisons, our results suggest that DNRA is also important under favorable conditions. KEY WORDS: DNRA · Denitrification · Nitrogen transformations · Ecotype · Season Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 65: [55][56][57][58][59][60][61][62][63][64] 2011 finally N 2 (Ye et al. 1995). The final reduction products, nitrous oxide (N 2 O), a potent greenhouse gas (Ramaswamy et al. 2001), and dinitrogen gas (N 2 ), are lost from the system into the atmosphere (Delwiche & Bryan 1976). In the presence of O 2 , most denitrifying bacteria will switch to the physiologically preferred process of aerobic respiration at the expense of NO 3 − reduction. (Megonigal et al. 2004). Denitrification may be diminished by the presence of free sulfides, which can inhibit the enzymes responsible for the final 2 stages of the process (Burgin & Hamilton 2007).DNRA is a microbial process that transforms NO 3 − to ammonium (NH 4 + ) via formation of NO 2 − in anaerobic or low O 2 environments. The final N form, NH 4 + , is bioavailable and readily immobilized by microbes and plants, or transformed by nitrification (Bengtsson et al. 2003). There are 2 DNRA pathways; fermentative and chemolithoautotrophic. Fermentative DNRA microbes reduce NO 3 − to NO 2 − to produce ATP. The subsequent reduction of NO 2 − to NH 4 + is an electron sink that allows re-oxidation of NADH (Tiedje 1988). Chemolithoautotrophic DNRA is the transformation of NO 3 − to NH 4 + , linked to oxidation of reduced sulfur (S) compounds. This sulfur-driven NO 3 − reduction leads to ...

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“…Under flooding, nitrate replaces oxygen as the terminal electron acceptor in microbial respiration leading to denitrification and/ or nitrate ammonification [23]. In fact, three nitrate reducing pathways are known in soils: (1) dissimilatory nitrate reduction to ammonia (DNRA or accumulators), (2) nitrogen dissimilating bacteria which are only able to reduce nitrate to nitrite ( accumulators) and (3) denitrifyiers that are able to reduce nitrate to nitrous oxide or to dinitrogen [5,7,27]. Bacterial reduction of nitrate is considered to be an important loss of available nitrogen from soils [3,19].…”

Section: Introductionmentioning

confidence: 99%

Influence of flooding on growth, nitrogen availability in soil, and nitrate reduction of young oak seedlings (Quercus robur L.)

et al. 2005

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-Oak (Quercus robur L.) seedlings were grown in pots under controlled conditions and submitted to 34 days of flooding followed by two-week drainage. Roots were significantly affected with reduced extension and dry weight accumulation. After drainage, biomass production of adventitious roots markedly increased in flooded seedlings. Flooding induced a sharp decrease in NO 3 --N content in the soil especially in the bottom of pots. NH 4 + -N concentrations increased significantly but at less level compared to NO 3 --N decreases. During flooding, root nitrate reductase activity (NRA) was similar to controls while leaf NRA was always below that of controls. The flooded roots maintained amino acid synthesis despite the nitrate depletion in soil. By contrast, leaf amino acid content decreased significantly in flooded seedlings especially at day 34. In flooded seedlings, the transfer of amino acid from cotyledons was disrupted but the transfer capacity was restored after drainage. Relationships between nitrate reduction and changes in soil mineral nitrogen availability are discussed.flooding / mineral nitrogen availability / nitrate reduction / Quercus robur L. Résumé -Influence de l'ennoyage sur la croissance, la biodisponibilité en azote du sol, et sur la réduction des nitrates chez de jeunes semis de chêne pédonculé (Quercus robur L.). Des semis de chêne pédonculé (Quercus robur L.) cultivés en conditions contrôlées ont été soumis à 34 jours d'ennoyage suivi de deux semaines de drainage. La longueur des racines stressées ainsi que leur accumulation de biomasse ont été significativement réduites. Après drainage, la biomasse des racines adventives des semis ennoyés a fortement augmenté. L'ennoyage a induit une forte diminution des teneurs en N-NO 3 -dans le sol, particulièrement dans les 5 cm inférieurs du pot. La concentration en N-NH 4 + a augmenté significativement mais sans compenser la diminution de N-NO 3 -. Pendant l'ennoyage, les activités nitrate réductase racinaires des deux lots étaient similaires alors que dans les feuilles elle était toujours inférieure chez les plants ennoyés. Les racines ennoyées ont maintenu la synthèse d'acides aminés malgré la disparition des nitrates dans le sol. Au contraire, la teneur en acides aminés dans les feuilles avait significativement diminué dans les semis ennoyés en particulier à 34 jours. Dans les semis ennoyés, le transfert des acides aminés depuis les cotylédons était perturbé, cependant après drainage la capacité de transfert était rétablie. Les relations entre la réduction des nitrates et les changements de la biodisponibilité de l'azote minéral du sol sont discutées. ennoyage / azote minéral disponible / réduction des nitrates / Quercus robur L.

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The influence of Glyceria maxima and nitrate input on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community

Cited by 37 publications

References 16 publications

Frequency and Diversity of Nitrate Reductase Genes among Nitrate-Dissimilating Pseudomonas in the Rhizosphere of Perennial Grasses Grown in Field Conditions

Frequency and Diversity of Nitrate Reductase Genes among Nitrate-Dissimilating Pseudomonas in the Rhizosphere of Perennial Grasses Grown in Field Conditions

Dissimilatory nitrate reduction pathways in an oligotrophic freshwater ecosystem: spatial and temporal trends

Influence of flooding on growth, nitrogen availability in soil, and nitrate reduction of young oak seedlings (Quercus robur L.)

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