Open AccessInfluence of copper on expression of nirS , norB and nosZ and the transcription and activity of NIR , NOR and N 2 OR in the denitrifying soil bacteria Pseudomonas stutzeri
Author(s) -
Black Amanda,
Hsu PeiChun L.,
Hamonts Kelly E.,
Clough Tim J.,
Condron Leo M.
Publication year - 2016
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.12352
Subject(s) - nitrous oxide reductase , nitrous oxide , chemistry , nitrite reductase , denitrifying bacteria , pseudomonas stutzeri , soil water , nitrate reductase , denitrification , copper , bacteria , nitric oxide , nitrite , enzyme , transcription (linguistics) , nitrate , food science , biochemistry , environmental chemistry , nitrogen , biology , organic chemistry , ecology , linguistics , philosophy , genetics
Summary Reduction of the potent greenhouse gas nitrous oxide (N 2 O) occurs in soil environments by the action of denitrifying bacteria possessing nitrous oxide reductase (N 2 OR ), a dimeric copper (Cu)‐dependent enzyme producing environmentally benign dinitrogen (N 2 ). We examined the effects of increasing Cu concentrations on the transcription and activity of nitrite reductase ( NIR ), nitric oxide reductase ( NOR ) and N 2 OR in Pseudomonas stutzeri grown anaerobically in solution over a 10‐day period. Gas samples were taken on a daily basis and after 6 days, bacterial RNA was recovered to determine the expression of nirS , norB and nosZ encoding NIR , NOR and N 2 OR respectively. Results revealed that 0.05 mM Cu caused maximum conversion of N 2 O to N 2 via bacterial reduction of N 2 O. As soluble Cu generally makes up less than 0.001% of total soil Cu, extrapolation of 0.05 mg l −l soluble Cu would require soils to have a total concentration of Cu in the range of, 150–200 μg g −1 to maximize the proportion of N 2 O reduced to N 2 . Given that many intensively farmed agricultural soils are deficient in Cu in terms of plant nutrition, providing a sufficient concentration of biologically accessible Cu could provide a potentially useful microbial‐based strategy of reducing agricultural N 2 O emissions.