A
Cor (
cold-
responsive) cDNA that belongs to the group-3
Lea (
late
embryogenesis
abundant)/
Rab (
responsive to
abscisic acid, ABA) family was isolated from a winter-hardy cultivar of common wheat (
Triticum aestivum L.). Screening of a cold-acclimated cDNA library was performed using an ABA- and other stress-responsive barley cDNA clone,
Hva1, as a probe. A wheat cDNA clone (designated as
Wrab19) putatively encoded a basic (pI=10.3) and hydrophobic protein with 179 amino acids. The deduced protein showed characteristics of the group-3 LEA/RAB protein family. In contrast to the single copy barley
Hva1,
Wrab19 belonged to a multigene family in the hexaploid wheat genome and six loci were assigned to the homoeologous group 1 chromosomes. Using
Wrab19 as a probe, four homologous cDNAs (designated as
Wrab17) were isolated that encoded acidic (pI=4.6-4.7) and hydrophobic proteins, all with 166 amino acids. The deduced proteins showed high homology (a mean of 84% identity) with a barley gibberellic acid (GA
3)-inducible protein, ES2A, and several other group-3 LEA/RAB proteins.
Wrab17 was considered to be a three-copy gene and each copy was assigned to chromosome 5A, 4B or 4D of hexaploid wheat. Transcripts of both
Wrab19 and
Wrab17 accumulated within 1 day of cold acclimation at 4°C. They were responsive to ABA and/or GA
3, but showed some cultivar differences in their response to these plant hormones. We conclude that the two genes are new members of the group-3
Lea/Rab-related
Cor gene family in wheat.
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