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

Glycyrrhiza uralensis 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 G. uralensis, designated GuDREB1 to GuDREB18. 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 G. uralensis DREBs with 61 Arabidopsis thaliana DREBs into five subgroups, indicating evolutionary conservation. Promoter analysis detected seventeen stress-responsive cis-acting elements, encompassing hormone-responsive and abiotic stress-responsive motifs, suggesting diverse biological functions. Tissue-specific expression profiling revealed GuDREB transcription in both aerial and underground parts. Drought stress induced varying degrees of GuDREB expression, confirming their involvement in stress responses. Notably, GuDREB10 expression increased significantly in underground parts, while GuDREB15 showed pronounced upregulation in aerial parts under drought; the GuDREB15 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 G. uralensis 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.