DROUGHT, HEAT AND SALT STRESS INDUCE THE EXPRESSION OF A CITRUS HOMOLOG OF AN ATYPICAL LATE-EMBRYOGENESIS LEA5 GENE

In a search for genes that are induced in citrus cell suspension in re sponse to salt stress, a cDNA done with high homology to cotton Lea5 g ene was isolated. Data base analysis of the protein deduced from the n ucleotide sequence indicates that, like in cotton, the protein from ci trus contains regions with significant hydropathic character. The gene , designated C-Lea5, is expressed in citrus leaves as well as cell sus pension. The steady-state level of C-Lea5 is increased in cell suspens ion that is grown in the presence of 0.2 M NaCl. This phenomenon is al so observed in leaves of citrus plants irrigated with NaCl and in citr us seedlings which are exposed to drought and heat stress. We suggest that the osmotic stress resulted from elevated level of salt is respon sible for the increase in the level of C-Lea5.