Jones et al. 2011 FEMS Microbiology Ecology Phenotypic and genotypic heterogeneityamong closely related soil-borneN2- andN2O-pr

http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6941.2011.01071.x/abst...

Little is known about the genetic and phenotypic diversity of Gram-positive
denitrifying bacteria. We compared the production of gaseous denitrification
products for 14 closely related Bacillus soil isolates at pH 6 and 7 during 48-h batch
incubations using a robotic gas-sampling apparatus. Primers targeting the nosZ
gene encoding the nitrous oxide reductase were designed to confirm the presence
of this gene in the isolates. The variation in the production of gaseous nitrogen
products was compared with the genetic variation based on 16S rRNA gene
sequences, genomic fingerprinting and nosZ sequences. The nosZ gene was
detected in all isolates and all produced N2 as the dominant end product at pH 7.
Production of gaseous nitrogen products was more variable at pH 6, with different
levels of NO and N2O production among the isolates, although minimal variation
was observed among the 16S rRNA and nosZ gene sequences. One isolate was more
divergent from the others based on genomic fingerprinting, and had two different
nosZ gene copies, which coincided with the highest production of N2 at pH 7 and
the lack of intermediates at pH 6. Overall, our analysis suggests that genetic
variation plays a role in the variation in N2O and N2 production, but the variation
in activity caused by acidification can be substantially greater than genotypic
variation among closely related Bacillus.