Wan, S., Greenham, T., Goto, K., Mottiar, Y., Johnson, A. M., Staebler, J. M., Zaidi, M. A., Shu, Q. and Altosaar, I. 2014. A novel nitrous oxide mitigation strategy: expressing nitrous oxide reductase from Pseudomonas stutzeri in transgenic plants. Can. J. Plant Sci. 94: 1013-1025. As a stable greenhouse gas, nitrous oxide (N₂O) plays a significant role in stratospheric ozone destruction. The primary anthropogenic N₂O source is the use of nitrogen in agriculture. Currently, the annual N₂O emissions from this soil-plant-microbial system is more than 2.6 Tg (1 Tg=1 million metric tonnes) of N₂O-N globally. So it is important to explore some innovative and effective biology-based strategies for N₂O mitigation. If shown to be effective in field trails as well as laboratory-scale experiments, such GMO plants could help guide international policies on adaptation to climate change. The bacterial enzyme nitrous oxide reductase (N₂OR) is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N₂O to N₂. To “scrub” the N₂O emissions, bacterial N₂OR was heterologously expressed in plants. Structurally, the enzyme N₂OR is encoded by nosZ, but its biosynthesis and assembly in prokaryotes require the products of several nos genes, including a putative ABC-type transporter encoded by nosDFY, and the copper chaperone NosL for biogenesis of the metal centre. We have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other nos genes were co-expressed under the control of a root-specific promoter (rolD) and a constitutive promoter (d35S). The nosZ gene from Pseudomonas stutzeri heterologously expressed in tobacco produced active recombinant N₂OR. The positive results in the preliminary proof-of-principle experiments indicated that plants heterologously expressing N₂OR could mitigate emissions at the source before N₂O reaches the stratosphere or troposphere.