Genome-wide Identification and Expression Analysis of the GRAS Gene Family in Beta vulgaris

To investigate the composition of the GRAS family in sugar beet（Beta vulgaris）and its regulatory functions in growth, development, and stress response, the GRAS gene family was identified and its expression was profiled using bioinformatic methods. Analyses were conducted on the physicochemical properties, subcellular localization, conserved domains, chromosomal distribution, and promoter cis-acting elements of the encoded proteins, along with their evolutionary relationships. Tissue-specific expression patterns of GRAS genes under drought conditions were further examined by integrating transcriptomic data from drought-stressed sugar beet. The results revealed that 38 GRAS genes were identified in the sugar beet genome, which were classified into nine subgroups and distributed across eight chromosomes. The encoded proteins ranged from 280 to 795 amino acids in length, with most being hydrophilic and predicted to localize primarily to the nucleus. Promoter analysis indicated that GRAS gene promoters are enriched in hormone-responsive and stress-related cis-acting elements. Transcriptomic analysis under drought stress showed that BvGRAS28 was significantly upregulated, suggesting a positive regulatory role in drought resistance, while BvGRAS9 and BvGRAS31 were significantly downregulated, indicating functional diversification among family members under drought conditions. Ten candidate BvGRAS genes were selected for qPCR validation, and the results confirmed their distinct tissue-specific expression patterns in sugar beet. In summary, this study provides preliminary insights into the potential functions of the GRAS gene family in sugar beet growth, development, and stress adaptation, offering a reference for subsequent functional validation of genes and molecular breeding for stress-resistant sugar beet.