Wan, S., Goto, K., Mottiar, Y., Staebler, J. M., Johnson, A. M., Voronova, A., Blais, D. R., Zaidi, M. A. and Altosaar, I. 2012. Bacterial nitrous oxide reductase expressed in transgenic plants: Evidence for sufficient anaerobicity to permit activity. Can. J. Plant Sci. 92: 1283-1294. Soil nitrogen enrichment practices enhance crop yields but greatly exacerbate the production and release of nitrous oxide (N₂O), a potent greenhouse gas. The conversion of N₂O to dinitrogen (N₂) in soil denitrifiers is normally driven by the anaerobic enzyme nitrous oxide reductase (N₂OR). Since this step is often limited in fertilised soils, we have transferred this unique microbial biocatalyst from the soil bacterium Pseudomonas stutzeri to transgenic Nicotiana tabacum plants. Our results confirm that engineered plants expressing the N₂OR structural gene nosZ are capable of producing functional reductase enzyme without the involvement of the native accessory gene products. Since bacterial N₂OR normally exists in the anaerobic environment of the soil bacterium's periplasmic space, this novel in planta activity suggests that plant cells can provide a similar hypoxic refuge for anaerobic enzyme activity. Genetically engineered crops containing N₂OR could have considerable potential in the phytoremediation of atmospheric N₂O.