Overexpression of the soybean (Glycine max) DRE-binding transcription factor GmDREB1 enhanced drought stress tolerance of transgenic wheat in the field.
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DREB (drought response element binding) like transcription factors can significantly enhance plant tolerance to drought. However, most research on DREB-like proteins to date has been conducted in growth chambers or greenhouses, so there is very little evidence available to support the application of DREB-like proteins in the field. Here, we overexpressed GmDREB1 from soybean in two popular wheat varieties and conducted several drought tolerance experiments across a range of years, sites and drought-stress regimes. We found that these plants consistently exhibited significant improvements in yield performance and a variety of physiological traits over WT plants when grown under limited water conditions in the field, for example showing grain yield increases between 4.79-18.43%. Specifically, we found that the transgenic wheat plants had reduced membrane damage and enhanced osmotic adjustment as well photosynthetic efficiency compared to non-transgenic controls. Three enzymes from the biosynthetic pathway of the phytohormone melatonin were up-regulated in transgenic wheat, further supporting a role for melatonin in the observed drought tolerance, external application of melatonin improved drought tolerance performance. Collectively, our results convincingly demonstrate the utility of a transgenic overexpression strategy for using GmDREB1 to improve wheat drought tolerance in the field.