Response of Nicotiana alata to insertion of an autoregulated senescence-inhibition gene

Nicotiana alata Link and Otto (Jasmine tobacco) was transformed with an aut oregulated senescence-inhibition gene construct P-SAGI2-IPT encoding isopen tenyl transferase via Agrobacterium-mediated transformation. Transformation was confirmed by polymerase chain reaction. Transgenic plants exhibited up to 2- to 4-fold fewer senesced leaves, 29% longer in situ flower life, 26% more shoot dry weight, and a 32% to 50% reduction in flowers per branch. A dditionally, transgenics were 28% shorter and had up to 174% more branches. indicative of cytokinin overproduction and a lack of tight autoregulation of P-SAG12-IPT. Variation among independent transgenics suggests selection for enhanced P-SAG12-IPT is feasible. Our observations of increased branchi ng and in situ flower longevity, as well as reduced plant height and flower s per branch provide new information on P-SAG12-IPT and its potential value for biological study and horticultural application.