Characterization of a DRE-binding transcription factor from a halophyte Atriplex hortensis

Abstract

Environmental stresses, such as salinity, drought and cold, can induce the expression of a large amount of genes. Among these are many transcription factors that regulate the expression of downstream genes by specifically binding to cis-elements or forming transcriptional complexes with other proteins. In the present study, a DREB-like transcription factor gene, named AhDREB1, was isolated from a halophyte Atriplex hortensis. AhDREB1 encoded a protein containing a conserved EREBP/AP2 domain featuring the DREB family. In yeast one-hybrid analysis AhDREB1 protein was specifically bound to DRE elements and activated the expression of the reporter genes of HIS3 and LacZ. The AhDREB1 gene was expressed in roots, stems and leaves of A. hortensis. Salinity induced its expression in roots, but not in other organs. Overexpression of AhDREB1 in transgenic tobacco led to the accumulation of its putative downstream genes. The performance of the transgenic lines was also tested under stressed conditions and two lines were found to be stress-tolerant. These results suggest that the AhDREB1 protein functions as a DRE-binding transcription factor and play roles in the stress-tolerant response of A. hortensis.

Role of Plant Transcription Factors in Abiotic Stress Tolerance

“…Likewise, the constitutively overexpressing CBF3/DREB1A and ABF3 transgenic rice showed better drought and salinity tolerance without any growth inhibition or phenotypic anomalies . The overexpression of AhDREB1 accumulated putative downstream target genes and also conferred improved survival rate to transgenic tobacco plants under salt stress as compared to the wild-type plants (Shen et al, 2003b). The over-expression of OsDREB1F greatly enhanced tolerance of plants to high salinity, drought, and lowtemperature both in rice and Arabidopsis, thus playing a significant role in plant stress signal transduction .…”

“…The activation of these transcripts is organ-specific and comparative to the extent of the stress given. When exposed to salt stress, AhDREB1 was highly expressed in roots but less significantly in stems and leaves (Shen et al, 2003b). It was observed that OsDREB1F was constitutively expressed throughout the plant with highest expression in panicles and callus than in the other tissues .…”

Soybean physiology and gene expression during drought

“…This is reasonable, since roots usually sense stress signals first, due to contact with the soil; plants need to express defense-related genes in their roots in time to promote survival under severe conditions (Li et al, 2005). Shen et al (2003) found that AhDREB1, a DREB-type gene from Arabidopsis hortensis, was induced in roots, but not in stems or leaves.…”

From Laboratory to Field. Using Information from Arabidopsis to Engineer Salt, Cold, and Drought Tolerance in Crops

“…The orthologous genes of CBF have been found in most crop plants examined so far, including canola (B. napus), soybean (Glycine max), broccoli (Brassica oleracea), tomato, alfalfa (Medicago sativa), tobacco (Nicotiana tabacum), cherry (Prunus avium), strawberry (Fragaria spp. ), wheat, rye (Secale cereale), corn (Zea mays), rice, and barley (Jaglo et al, 2001;Choi et al, 2002;Gao et al, 2002;Owens et al, 2002;Dubouzet et al, 2003;Francia et al, 2004;Shen et al, 2003aShen et al, , 2003bVagujfalvi et al, 2003;Xue, 2003). Many of the putative orthologs have been functionally tested, indicating conservation of the pathway in those plant species.…”