Identification and characterization of a novel barley gene that is ABA-inducible and expressed specifically in embryo and aleurone

A screening of a cDNA library of abscisic acid (ABA)-treated barley aleuron e using a polyclonal anti-idiotypic antibody that had been made against an anti-ABA monoclonal antibody resulted in the isolation of a cDNA clone aba4 5. Northern blot analysis showed that aba45 was up-regulated by ABA and dow n-regulated by gibberellin. Aba45 mRNA was not detectable in barley roots, stems and leaves and was most abundant in developing aleurone and embryo. A nalysis of the 5' genomic sequence of aba45, isolated using a nested PCR pr ocedure, revealed a conserved ABA response complex that consists of an AGGT -core element and a conserved gibberellin response element.