The drought response displayed by a DRE-binding protein from Triticum dicoccoides

Drought is one of the major causes of dramatic yield loss in crop plants. Knowledge of how to alleviate this loss is still limited due to the complexity of both the stress condition and plant responses. Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is a potential source of important drought-resistance genes for its cultivated relatives. The gene for an emmer DRE-binding protein, TdicDRF1, was cloned and shown to be drought-responsive with orthologs in other plants. This is the first report of the cloning of TdicDRF1, and its expression was further characterized by RT-PCR in both drought-sensitive and drought-resistant accessions of Triticum dicoccoides. Analysis of the AP2/ERF DNA-binding domain of TdicDRF1 as a GST-fusion protein and its binding to DRE by electrophoretic mobility shift assay (EMSA) indicate functional differences between wheat DREBs and those characterized in Arabidopsis thaliana. DREB expression increased in drought-stressed roots, correlating with the RT-PCR results, but not in leaf, showing that tissue-specific regulation occurs at the protein level. Hence, the DREB–DRE interaction undergoes subtle multi-level regulation.

Research highlights
► First characterisation of a DREB transcription factor in wild emmer wheat, TdicDRF1.
►  TdicDRF1 is specifically upregulated in drought-tolerant wheat.
► Contrasting expression patterns are shown between root and above-ground tissues.
► TdicDRF1 has altered DNA binding specificity from previously characterised DREBs.