Cloning of TaCYP707A1 Gene that Encodes ABA 8′-Hydroxylase in Common Wheat (Triticum aestivum L.)

The plant hormone abscisic acid (ABA) regulates many important physiological and developmental processes in plants. The objective of this study was to clone the ABA 8'-hydroxylase gene in common wheat. In the present study, we used the cDNA sequence of barley HvCYP707A1 gene (GenBank accession no. AB239299) as a probe for BLAST search against the common wheat (Triticum aestivum L.) EST database in GenBank. All wheat ESTs sharing high similarity with the reference gene were subjected to contig assembly. Primers were designed based on the constructed contigs to clone the wheat CYP707A1 gene, designated as TaCYP707A1. The genomic DNA sequence of TaCYP707A1 gene comprised five exons and four introns, with a size of 2 225 bp. The corresponding cDNA sequence of TaCYP707A1 was 1 737 bp, containing an open reading frame (ORF) of 1 431 bp, a 42-bp 5'-untranslated region (UTR) and a 264-bp 3'UTR, with 94.9% of identical sequences to HvCYP707A1 gene (AB239299). The neighbor joining tree indicated that the deduced amino acid sequences of TaCYP707A1 gene was highly similar to those of barley and rice. The TaCYP707A1 gene was located on chromosome 6BL using a set of Chinese Spring nullisomic-tetrasomic lines and ditelosomic line 6BS. These results will be of high importance in understanding of molecular mechanism of ABA catabolism.