Expression of nitrous oxide reductase from Pseudomonas stutzeri in transgenic tobacco roots using the root‐specific rolD promoter from Agrobacterium rhizogenes

摘要

AbstractThe nitrous oxide (N₂O) reduction pathway from a soil bacterium, Pseudomonas stutzeri, was engineered in plants to reduce N₂O emissions. As a proof of principle, transgenic plants expressing nitrous oxide reductase (N₂OR) from P. stutzeri, encoded by the nosZ gene, and other transgenic plants expressing N₂OR along with the more complete operon from P. stutzeri, encoded by nosFLZDY, were generated. Gene constructs were engineered under the control of a root-specific promoter and with a secretion signal peptide. Expression and rhizosecretion of the transgene protein were achieved, and N₂OR from transgenic Nicotiana tabacum proved functional using the methyl viologen assay. Transgenic plant line 1.10 showed the highest specific activity of 16.7 µmol N₂O reduced min−1 g−1 root protein. Another event, plant line 1.9, also demonstrated high specific activity of N₂OR, 13.2 µmol N₂O reduced min−1 g−1 root protein. The availability now of these transgenic seed stocks may enable canopy studies in field test plots to monitor whole rhizosphere N flux. By incorporating one bacterial gene into genetically modified organism (GMO) crops (e.g., cotton, corn, and soybean) in this way, it may be possible to reduce the atmospheric concentration of N₂O that has continued to increase linearly (about 0.26% year−1) over the past half-century.