Water stress-regulated gene expression in Cicer arietinum seedlings and plants

Water stress induces biochemical and physiological responses in plants, suc h as growth inhibition. A number of genes that respond to drought stress in Cicer arietinum are described and their expression patterns are studied in order to give an approach of their function. Genes coding for lipid transf er proteins (LTP) and late embryogenesis abundant (LEA) proteins seem to be important in chickpea water stress response. The induction of these genes is not exclusive of osmotic stress caused by polyethylene glycol, since the y also showed a significant up-regulation by high salinity. These genes are not responsive to exogenous abscisic acid (ABA) treatment. CapLTP was main ly expressed in young tissues: messengers are more abundant in seedlings th an in adult plants, and the transcript level decreased gradually as the age of epicotyls increased. In this sense, LTPs would be involved in cuticle s ynthesis during early developmental stages. CapLEA-1 and CapLEA-2 are marke dly up-regulated by NaCl treatment in every seedling sections. The response of these genes to high salinity suggests their implication in protection o f cellular functions from high ion concentration damage. Present results ag ree with the postulated role for group 3 LEAs in sequestering ions, thus pa lliating toxic effects of NaCl. The presence of LEAs in vegetative well-wat ered tissues suggests a new function for these proteins. Other cDNAs encodi ng glyoxalases, proline-rich proteins and raffinose synthases have also bee n identified as induced by water stress. (C) 2001 Editions scientifiques et medicales Elsevier SAS.