Objective To screen, identify, and analyze the FsUGTs family from Forsythia suspensa based on transcriptomic data. Methods The FsUGTs gene family of F. suspensa was identified from transcriptomic and genomic data. Bioinformatics techniques were applied for comprehensive analysis to explore the physicochemical properties and subcellular localization of the proteins encoded by these genes. The evolutionary relationships among these gene family members were further revealed through phylogenetic tree construction, chromosomal localization, cis-acting element analysis, conserved motif analysis, domain analysis, and gene structure analysis. In addition, RT-qPCR was used to detect the expression patterns of FsUGTs in different tissues (roots, stems, leaves, and fruits), and correlation analysis was performed by integrating these results with the tissue distribution of phillyrin. Results After screening and identification in the F. suspensa transcriptome data, a total of 82 FsUGTs were finally obtained. Their amino acid lengths ranged from 385 to 558 amino acids (aa), relative molecular masses from 43 140—60 750, and theoretical isoelectric points (pI) from 4.81 to 8.26. These proteins are primarily localized to the plasma membrane and all contain the PSPG box domain. Phylogenetic analysis classified the 82 FsUGTsinto 17 groups: Group L contained the highest number of UGTs (16 members), followed by Groups A and E with ten and nine respectively, while no FsUGTs were distributed in Group Q. Chromosomal localization results showed that 16 FsUGTs were located on Chr10, with seven each on Chr11, Chr12, and Chr13, while Chr3 contained the fewest FsUGTs (only two). Analysis of cis-acting elements indicated that the expression of FsUGTs was most strongly influenced by light, followed by methyl jasmonate. Domain analysis revealed that all 82 FsUGTs contained three conserved domains, namely GT1_Gtf-like, PLN02448, and Glycosyltransferase_GTB-type superfamily. Correlation analysis between tissue-specific expression of FsUGTs and phillyrin content in different tissues indicated that FsUGT1-FsUGT3, FsUGT9, FsUGT12-FsUGT16, FsUGT18, FsUGT21-FsUGT24, and FsUGT31 may play roles in the glycosylation of phillygenin to form phillyrin. Conclusion This study identified and analyzed the physicochemical properties, cis-acting elements, protein structures, phylogenetic relationships, and tissue-specific expression of the FsUGTs family from F. suspensa. It also screened FsUGTs that may be involved in the glycosylation of phillygenin to phillyrin, laying a foundation for the further identification of phillygenin glycosyltransferases and the understanding of the regulatory mechanisms underlying the synthesis of medicinal components in F. suspensa.

Forsythia suspensa (Thunb.) Vahl  /  UGT gene family  /  phillyrin  /  tissue-specific differential expression  /  chromosome localization