Expression of three ABA-regulated clones and their relationship to maturation processes during the embryogenesis of chick-pea seeds

Water stress inhibits germination of chick-pea seeds and produces specific changes in gene expression. some of which are coincident with those induced by the exogenous application of abscisic acid (ABA). Three cDNA clones, GAB-8, GAB-9 and GAB-11, were previously identified as under the regulation of ABA and osmotic stress in embryonic axes of germinating chick-pea. Here we try to establish a relationship between the changes in gene expression induced by ABA and stress conditions during germination and those naturally occurring during the desiccation process that leads to seed maturation. Our results show that the germinative capacity of chick-pea is related to the water content of the organ. In vitro translation of the mRNAs from developing seed reveals that in the later stages of seed maturation some polypeptides appear that previously were found to be regulated by ABA and by water deficit in germinating seeds. Hybridization by northern blot of embryogenic mRNAs with GAB-8. GAB-9 and GAB-11 clones shows that the mRNAs corresponding to such clones only appear in the later phases of seed formation, coinciding with seed dehydration, and persisting until seeds became fully mature. The results suggest that these mRNAs are probably related to the response to dehydration that occurs during seed maturation, and that the pattern of expression of these ABA-regulated clones coincides with that of the established late embryogenesis-abundant (LEA) genes.