STRUCTURE OF THE DEHYDRIN TAS14 GENE OF TOMATO AND ITS DEVELOPMENTAL AND ENVIRONMENTAL-REGULATION IN TRANSGENIC TOBACCO

We have isolated a genomic clone encoding tomato TAS14, a dehydrin tha t accumulates in response to mannitol, NaCl or abscisic acid (ABA) tre atment. A fragment of tas14 gene containing the region from -2591 to 162 fused to beta-glucuronidase gene drives ABA- and osmotic stress-in duced GUS expression in transgenic tobacco. Histochemical analysis of salt-, mannitol- and ABA-treated plants showed GUS activity mainly loc alized to vascular tissues, outer cortex and adventitious root meriste ms, coinciding with the previously observed distribution of TAS14 prot ein in salt-stressed tomato plants. In addition, GUS activity was also observed in guard cells, trichomes and leaf axils. Developmentally re gulated gus expression was studied in unstressed plants and found to o ccur not only in embryos, but also in flowers and pollen. Tas14 expres sion in floral organs was confirmed by northern blots of tomato flower s.