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Denitrification by Rhizobium meliloti

Abstract

Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using a nosZ probe derived from the Pseudomonas stutzeri. To decide whether R. meliloti strains used as inoculants contribute to the total denitrification activity in a lucerne ley, strains with different denitrifying capacities were used in field and laboratory experiments. The nitrate reduction activity of R. meliloti during anaerobic respiration was compared with that of a strain of Pseudomonas aeruginosa. A great diversity in the denitrification activity was found within strains of R. meliloti, and four of thirteen investigated strains showed an obvious denitrification activity. Two denitrifying bacteria were used as references, one strain each of Bradyrhizobium japonicum and P. aeruginosa. All but one of the R. meliloti strains hybridized to the PstI-fragment of the nosZ-gene from P. stutzeri. Two sizes of the hybridizing fragment, 5 and 7 kb, were noticed. Nos activity was only shown in three R. meliloti strains, and these were all characterized by a high denitrification activity. The potential denitrification activity was about 20, 40, and 80 times higher than the  More>>
Authors:
Publication Date:
Oct 01, 1996
Product Type:
Thesis/Dissertation
Report Number:
SLU-MIKRO-R-65
Reference Number:
SCA: 540220; PA: SWD-96:007510; EDB-96:152348; NTS-97:003335; SN: 96001673409
Resource Relation:
Other Information: TH: Thesis (FL); PBD: 1996
Subject:
54 ENVIRONMENTAL SCIENCES; DENITRIFICATION; RHIZOBIUM; LEGUMINOSAE; ROOTS; SYMBIOSIS; NITROGEN; NITROGEN FIXATION; NITROUS OXIDE; AIR POLLUTION CONTROL
OSTI ID:
378189
Research Organizations:
Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Microbiology
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0348-4041; Other: ON: DE97703162; TRN: SE9607510
Availability:
OSTI as DE97703162
Submitting Site:
SWD
Size:
76 p.
Announcement Date:

Citation Formats

Rosen, A. Denitrification by Rhizobium meliloti. Sweden: N. p., 1996. Web.
Rosen, A. Denitrification by Rhizobium meliloti. Sweden.
Rosen, A. 1996. "Denitrification by Rhizobium meliloti." Sweden.
@misc{etde_378189,
title = {Denitrification by Rhizobium meliloti}
author = {Rosen, A}
abstractNote = {Rhizobium meliloti strains were investigated for their denitrification activity as free-living cells and in nodules on lucerne (Medicago sativa) roots. They were also investigated for presence of nitrous oxide reductase (nos) activity and for genes using a nosZ probe derived from the Pseudomonas stutzeri. To decide whether R. meliloti strains used as inoculants contribute to the total denitrification activity in a lucerne ley, strains with different denitrifying capacities were used in field and laboratory experiments. The nitrate reduction activity of R. meliloti during anaerobic respiration was compared with that of a strain of Pseudomonas aeruginosa. A great diversity in the denitrification activity was found within strains of R. meliloti, and four of thirteen investigated strains showed an obvious denitrification activity. Two denitrifying bacteria were used as references, one strain each of Bradyrhizobium japonicum and P. aeruginosa. All but one of the R. meliloti strains hybridized to the PstI-fragment of the nosZ-gene from P. stutzeri. Two sizes of the hybridizing fragment, 5 and 7 kb, were noticed. Nos activity was only shown in three R. meliloti strains, and these were all characterized by a high denitrification activity. The potential denitrification activity was about 20, 40, and 80 times higher than the actual denitrification activity for lucerne, fallow, and grass, respectively. The potential denitrification activity was almost the same in lucerne and grass planted soils. Compared with the unplanted soil, the presence of lucerne roots in the soil increased the actual denitrification activity, while roots of both plant species, grass and lucerne, increased the potential denitrification activity in the soil. 32 refs, 7 figs, 1 tab}
place = {Sweden}
year = {1996}
month = {Oct}
}