CHANGES IN TRANSLATABLE MESSENGER-RNAS IN WATER-STRESSED COMMON BEAN GENOTYPES OF CONTRASTING DROUGHT TOLERANCE

We wanted to determine if the adaptation of common beans to water stre ss is associated with changes in gene expression. Therefore, we compar ed the changes occurring in the populations of leaf and root translata ble mRNAs of two drought-sensitive and two drought-tolerant genotypes after their exposition to a water stress of ten days. Approximately te n transcripts were induced or markedly increased in leaves of water-st ressed plants whereas four transcripts newly appeared in water-stresse d roots. In both tissues, none of the water-stress induced changes wer e found to be specific to the drought tolerant genotypes. Translation of leaf mRNAs in the presence of [H-3]glycine showed that some of the down- and some of the up-regulated transcripts are rich in glycine. Th e similarity of the gene response between drought-tolerant and drought -sensitive genotypes does not reflect the differences in their adaptat ion to drought.