Objective To study the characteristics and potential functions of sea buckthorn (Hippophae rhamnoides) and to analyze the biosynthesis mechanism and accumulation pattern of flavonoid glycosides by identifying the UGT gene family members in sea buckthorn.

Method  BLASTP and hmmsearch were used to identify the members of the HrUGT gene family based on sea buckthorn genome database. The protein physical and chemical properties, phylogenesis, protein motif and gene structure and gene duplication were analyzed by using Prot-Param, MUSCLE, MAGA7.0, MEME and MCScanX.

Result  89 HrUGTs containing the plant secondary product glycosyltransferase motif (PSPG) were identified from the sea buckthorn genome. The length of sea buckthorn UGT proteins ranged from 266 to 533 amino acids, the average molecular weight was 50.00 KDa, and the average isoelectric point was 5.89. According to the phylogenetic relationship, the 89 HrUGTs could be divided into 16 major groups. 84 HrUGTs were distributed on 11 chromosomes except chromosome 7. Tandem duplication was a predominant duplication event which caused the expansion of HrUGT genes. Transcriptomic data and RT-qPCR analysis indicated that most of UGT genes had a wide range of fruit development stage expression characteristics.

Conclusion The complete information of the HrUGT gene family is obtained, which will benefit the study on the biological functions of HrUGTs.