Transgenic tobacco expressing Vitreoscilla hemoglobin exhibits enhanced growth and altered metabolite production.

The gene for Vitreoscilla hemoglobin (VHb) has been introduced and expressed in Nicotiana tabaccum (tobacco). Transgenic tobacco plants expressing VHb exhibited enhanced growth, on average 80-100% more dry weight after 35 days of growth compared to wild-type controls. Furthermore, germination time is reduced from 6-8 days for wild-type tobacco to 3-4 days and the growth phase from germination to flowering was 3-5 days shorter for the VHb-expressing transgenes. Transgenic plants contained, on average, 30-40% more chlorophyll and 34% more nicotine than controls. VHb expression also resulted in an altered distribution of secondary metabolites: In the trangenic tobacco plants anabasine content was decreased 80% relative to control plants.