ANTISENSE APPLE ACC-OXIDASE RNA REDUCES ETHYLENE PRODUCTION IN TRANSGENIC TOMATO FRUIT

Transgenic tomato (Lycopersicon esculentum) plants were produced which expressed antisense copies of an apple fruit ACC-oxidase RNA. In the fruit of the primary transformants, ethylene production was reduced by over 95% in one of the lines assessed, and to a lesser extent in the other lines. The line showing the greatest reduction in ethylene produ ction showed a delay in the development of colour in the transgenic fr uit. Northern analysis of steady-state RNA levels using strand-specifi c probes indicated that fruit of the low-ethylene line had very low le vels of ACC-oxidase sense-RNA, and high levels of antisense RNA. In ot her lines, high levels of antisense RNA were not always associated wit h a reduction in the levels of either sense-transcript or ethylene pro duction. The successful reduction in ethylene production confirms the usefulness of using tomato as a model system for testing specific ripe ning-related genes from heterologous fruit species such as apple. Copy right (C) 1997 Elsevier Science Ireland Ltd.