Physiological and biochemical characteristics of tobacco transgenic plants expressing bacterial dioxygenase

Expression of the 1,2-dihydroxynaphthalene dioxygenase (nahC) gene from Pseudomonas putida in tobacco transgenic plants produces notable phenotypic and biochemical changes: retarded growth and rooting and earlier flowering; chlorotic and necrotic spots on leaves; and a threefold increase in the total phenolics in the leaves of 6-week-old plants (94.51 mug/g fr wt as compared to 33.18 mug/g fr wt in the control) and in the phenylalanine-ammonia lyase activity in 4-week-old plants (0.035 U/g fr wt as compared to 0.014 U/g in the control plants of the same age). The transgenic plants expressing the nahC bacterial gene may serve as a model to study the putative functions of dioxygenases and phenol compounds in plant growth, development, and stress responses.