Robert A. Sanford Darlene D. Wagner Qingzhong Wu Joanne C. Chee-Sanford Sara H. Thomas Claribel Cruz-García Gina Rodríguez Arturo Massol-Deyá Kishore K. Krishnani Kirsti M. Ritalahti Silke Nissen Konstantinos T. Konstantinidis and Frank E. Löffler. Unexpected nondenitrifier nitrous oxide reductase gene diversity and abundance in soils. PNAS 2012
Agricultural and industrial practices more than doubled the intrinsic rate of terrestrial N fixation over the past century with drastic consequences including increased atmospheric nitrous oxide (N2O) concentrations. N2O is a potent greenhouse gas and contributor to ozone layer destruction and its release from fixed N is almost entirely controlled by microbial activities. Mitigation of N2O emissions to the atmosphere has been attributed exclusively to denitrifiers possessing NosZ the enzyme system catalyzing N2O to N2 reduction. We demonstrate that diverse microbial taxa possess divergent nos clusters with genes that are related yet evolutionarily distinct from the typical nos genes of denitirifers. nos clusters with atypical nosZ occur in Bacteria and Archaea that denitrify (44% of genomes) do not possess other denitrification genes (56%) or perform dissimilatory nitrate reduction to ammonium (DNRA; (31%). Experiments with the DNRA soil bacterium Anaeromyxobacter dehalogenans demons
