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 g/g fr wt as compared to 33.18 g/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.     

Morphology and Phytohormone Content in Transgenic Tobacco Plants Expressing Bacterial Thermostable Cellulase

Expression of the bacterial gene for thermostable -1,4-glucanase (cellulase) from Clostridium thermocellum in transgenic tobacco plants was shown to produce significant changes in tobacco plant structure and activities. The transgenic plants differed in their growth rate and morphology, and their hormonal status was affected. Thus, the transgenic plants expressing the gene for thermostable bacterial cellulase are a convenient model to study the role of -1,4-glucanases in plant physiological processes.