BIPHASIC STIMULATION OF TRANSLATIONAL ACTIVITY CORRELATES WITH INDUCTION OF TRANSLATION ELONGATION-FACTOR-1 SUBUNIT-ALPHA UPON WOUNDING IN POTATO-TUBERS

Potato (Solanum tuberosum) tubers exhibit an increase in translational activity in response to mechanical wounding. The response is biphasic , with an initial stimulation apparent within the first 2 h after woun ding and a second increase occurring 12 to 24 h after wounding. Increa sed activity is apparent by measurement of protein synthesis both in v ivo and in vitro using a cell-free extract. Accumulation of the transl ational elongation factor 1 subunit alpha (EF-1 alpha) parallels trans lational activity. Changes in the steady-state level of EF-1 alpha mRN A, and expression of a chimeric EF-1 alpha promoter/beta-glucuronidase construct in transgenic potato tubers, indicate that the gene encodin g EF-1 alpha is transcribed during both periods of translational stimu lation. These results indicate that stimulation of translational activ ity is coordinated with increased expression and accumulation of trans lation factors.