MOLECULAR-CLONING AND CHARACTERIZATION OF 9 CDNAS FOR GENES THAT ARE RESPONSIVE TO DESICCATION IN ARABIDOPSIS-THALIANA - SEQUENCE-ANALYSIS OF ONE CDNA CLONE THAT ENCODES A PUTATIVE TRANSMEMBRANE CHANNEL PROTEIN

We isolated nine cDNAs for genes of Arabidopsis thaliana that are induced by the effects of water deficit by using the technique of differential hybridization and named them RD (RD for Responsive to Desiccation). The timing of induction of their mRNAs varies between these RD genes. Abscisic acid induces mRNAs that correspond to clones designated RD22 and RD29 but not to those designated RD19, RD21 and RD28, indicating that there are several signal-transduction pathways from water stress to expression of RD genes. Sequence analysis of the cDNA clone RD28 revealed that RD28 encodes a membrane protein with sequence homology to the major intrinsic protein of bovine lens fiber gap junction, soybean nodulin-26 and the glycerol facilitator from Escherichia coli, indicating that the putative RD28 protein is a member of the family of transmembrane channel proteins.