THE PLANT ONCOGENE ROLD STIMULATES FLOWERING IN TRANSGENIC TOBACCO PLANTS

The Agrobacterium rhizogenes T-DNA oncogene rolD under the control of its own 5' regulatory region was transferred to day-neutral tobacco pl ants. The main trait induced by roll) in transgenic plants is a striki ng precocity in newer setting and a strong enhancement of the flowerin g potential. In rolD plants, early flowering is followed by the very r apid growth of numerous lateral inflorescences. The analysis of severa l morphological and histological parameters suggests that some charact eristic morphological abnormalities observed in rolD plants can be acc ounted for by their early reproductive phase transition and points to the involvement in the transition of a greater portion of the plant bo dy than is the case for untransformed tobacco. The in vitro morphogeni c potential of tissues from rolD plants was also tested. Superficial t hin cell layer explants from rolD plants show an earlier and much enha nced newer organogenesis, compared to controls, both on flowering and on hormone-free medium. (C) 1996 Academic Press, Inc.