Structure and expression of an alcohol dehydrogenase 1 gene from Pisum sativum (cv. "Greenfeast")

Three genomic clones for anaerobically inducible alcohol dehydrogenase (Adh) have been isolated from Pisum sativum cv. "Greenfeast" via cDNA cloning. One of these contains a complete gene, has exon sequences corresponding to one of the cDNA sequences and is likely to be an expressed gene. This gene has a structure similar to the Adh genes of maize, with introns in the same positions in the coding sequence but differing in their lengths and nucleotide sequences. At the nucleotide level the coding sequence is 75% homologous to both maize Adh1 and Adh2 and 80% homologous to the Adh gene from Arabidopsis, but has an extra coding triplet in exon 1 that is not found in the other plant Adh genes. The non-translated regions of all the gene transcripts are widely divergent between species. A short segment of the pea Adh promoter region (-290 to +57) was fused to a reporter gene and introduced into protoplasts of Nicotiana plumbaginifolia by electroporation. Transient expression of the introduced gene increased markedly when the transfected protoplasts were incubated under anaerobic conditions, showing that cis-acting regulatory signals necessary for anaerobic control of expression reside in the -290 to +57 segment. Sequence comparisons between this region and the corresponding regions of maize and Arabidopsis Adh genes have identified short sequences that may be involved in the anaerobic regulation of plant Adh genes.