Bioinformatics Analysis and Expression Profiling Under Abiotic Stress of the DREB Gene Family in Glycyrrhiza uralensis

<i>Glycyrrhiza uralensis</i> is an important medicinal plant exhibiting strong tolerance to abiotic stresses, including drought and salinity. DREB (Dehydration-Responsive Element-Binding) transcription factors, key members of the AP2/ERF family, play crucial roles in plant growth, development, and stress responses. Based on transcriptome data, we identified 18 DREB transcription factors in <i>G. uralensis</i>, designated <i>GuDREB1</i> to <i>GuDREB18</i>. Bioinformatics analysis revealed genomic sequences ranging from 534 to 2864 bp and coding sequence (CDS) lengths between 525 and 1509 bp. All GuDREB proteins contain a single AP2 domain, including the conserved YRG and RAYD elements, and were predicted to localize to the nucleus. Phylogenetic analysis clustered the <i>G. uralensis</i> DREBs with 61 <i>Arabidopsis thaliana</i> DREBs into five subgroups, indicating evolutionary conservation. Promoter analysis detected seventeen stress-responsive <i>cis</i>-acting elements, encompassing hormone-responsive and abiotic stress-responsive motifs, suggesting diverse biological functions. Tissue-specific expression profiling revealed <i>GuDREB</i> transcription in both aerial and underground parts. Drought stress induced varying degrees of <i>GuDREB</i> expression, confirming their involvement in stress responses. Notably, <i>GuDREB10</i> expression increased significantly in underground parts, while <i>GuDREB15</i> showed pronounced upregulation in aerial parts under drought; the <i>GuDREB15</i> promoter contained the highest number of light-responsive elements (23), potentially explaining its aerial tissue specificity. Drought stress significantly increased abscisic acid (ABA) content. Underground parts exhibited higher initial sensitivity to drought, whereas aerial parts displayed a more sustained response; ABA levels overall showed an initial increase followed by a decline. This study expands the <i>G. uralensis</i> DREB gene database, provides a foundation for selecting stress-resistance genes, and offers insights into DREB functional roles in abiotic stress responses in this key medicinal species.