Soybean DRE-binding transcription factors that are responsive to abiotic stresses

Abstract

Three DREB homologue genes, GmDREBa, GmDREBb, and GmDREBc, were isolated from soybean, Glycine max (L.) Merr. Each of the deduced proteins contains an AP2 domain of 64 amino acids. Yeast one-hybrid assay revealed that all of the three dehydration-responsive, element-binding proteins specifically bound to the dehydration-responsive element. Analysis of transcriptional activation abilities of these proteins in yeast indicated that GmDREBa and GmDREBb could activate the expression of a reporter gene, whereas GmDREBc could not. The transcriptions of GmDREBa and GmDREBb were induced by salt, drought, and cold stresses in leaves of soybean seedlings. The expression of GmDREBc was not significantly affected in leaves but apparently induced in roots by salt, drought, and abscisic acid treatments. These results suggest that these three genes function specifically in response to abiotic stresses in soybean.