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

In order to explore the composition of the GRAS family members in sugar beet (Beta vulgaris) and their regulatory functions in the growth and development and stress response, the GRAS gene family was identified and its expression was profiled by using the bioinformatic methods. Then, the evolutionary relationships such as physicochemical properties, subcellular localization, conserved structure, chromosome localization, and promoter cis-acting elements of the encoded protein were discussed. And the expression pattern of GRAS in different tissues of sugar beet was analyzed by combining the drought transcriptome of sugar beet. The results showed that 38 GRAS genes were identified in the sugar beet genome, which could be classified into 9 subgroups and distributed across 8 different 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. The promoter cis-acting element analysis showed that GRAS gene members were enriched in hormone-responsive and stress response elements. Through the transcriptomic analysis of sugar beet under drought stress, it was found that the expression of BvGRAS28 was significantly up-regulated under drought, which may positively regulate the drought resistance response of sugar beet. However, BvGRAS9 and BvGRAS31 were significantly down-regulated, indicating that the family genes had functional differentiation under drought stress conditions. Ten candidate BvGRAS genes were screened for qPCR verification, and the results showed that these genes had obvious tissue specificity in sugar beet. In summary, the results of this study preliminarily revealed the potential function of the GRAS gene gene family in the growth and development and stress adaptation of sugar beet, which provided a reference for subsequent gene function verification and stress resistance breeding of sugar beet.