Abstract
AP2/ERF-type transcription factors DREBs specifically interact with the DRE/CRT cis-acting element and control the expression of many abiotic stress-inducible genes in Arabidopsis. Soybean is a globally important crop and genetically modified varieties are largely produced. To develop abiotic stress tolerant transgenics we analyzed function of DREB-type transcription factors in soybean.
To identify soybean DREB-type transcription factors containing an AP2/ERF domain, we performed soybean microarray analysis. We identified six DREB-like genes which were strongly induced by cold, drought, and salt stresses. Two of six DREB-like proteins exhibited transactivation activity in the Arabidopsis mesophyll protoplasts. We named them GmDREB1A and GmDREB2A. These proteins accumulated in nuclei and exhibited high transactivation activity in the soybean stem protoplasts. Overexpression of GmDREB2A in Arabidopsis plants resulted in upregulation of some genes related to heat shock and consequently these transgenic plants showed improved heat stress tolerance. These results indicate that GmDREB2A functions as a transcriptional activator in the heat-stress-responsive gene expression.
