PRODUCTION OF HIGH SOLIDS TOMATOES THROUGH MOLECULAR MODIFICATION OF LEVELS OF THE PLANT-GROWTH REGULATOR CYTOKININ

Chimeric isopentenyl transferase (ipt) gene constructs were prepared and introduced into tomato plants via Agrobacterium-mediated transformation. Expression of the ipr gene, which encodes a key enzyme involved in the biosynthesis of the plant growth regulator cytokinin, was modulated using a promoter from a gene expressed primarily in tomato ovaries. As expected, the ipt gene was expressed, and levels of cytokinin were increased, in ovaries of the transgenic plants. Plant yield and fruit processing characteristics of these transgenic plants were examined during three consecutive years of field testing. Levels of total solids were significantly increased in six of seven, and soluble solids were significantly increased in five of seven, independent transgenic tomato lines.