Identification of DREB gene family in foxtail millet (Setaria italica) and analysis of its expression pattern in response to abiotic stress

Dehydration response element binding proteins (DREBs) play a vital role in transcriptional regulators in enhancing plant tolerance to abiotic stress. To investigate the biological functions of the DREB gene family (<i>SiDREBs</i>) in foxtail millet (<i>Setaria italica</i>), this study performed bioinformatics and gene expression analysis on <i>SiDREBs</i> under abiotic stress. A total of 166 family members of <i>SiDREBs</i> were identified, which were classified into six subfamilies. <i>SiDREBs</i> were unevenly distributed on nine chromosomes, and were designated as <i>SiDREB1</i>-<i>166</i> based on their chromosomal positions. Covariance analysis revealed that <i>SiDREBs</i> were much more closely related to monocotyledonous plants sorghum, maize, and rice than to dicotyledonous plants <i>Arabidopsis thaliana</i>, tomato, and soybean. Promoter <i>cis</i>-acting element analysis showed that <i>SiDREBs</i> contained stress-related <i>cis-</i>acting elements. Under saline-alkali stress, <i>SiDREB153</i> exhibited significantly different expression levels between the resistant and susceptible materials, indicating that it plays a positive regulatory role in the response of foxtail millet to saline-alkali stress. Among different abiotic stresses, the expression of <i>SiDREB80</i> increased under drought, saline-alkali, and shade stress, that of <i>SiDREB4/129/131</i> rose under saline-alkali and high temperature stress, and that of <i>SiDREB159</i> increased under herbicide and saline-alkali stress. These genes play an important role in the response of foxtail millet to stress. These findings provide a theoretical basis for further studies on the function of <i>SiDREBs</i> in response to abiotic stress.