[Terpene synthase gene family in <i>Jasminum sambac</i> var. <i>Fuzhou bifoliatum</i>: genome-wide analysis and expression pattern in response to methyl jasmonate].

Terpene synthases (TPSs) play a crucial role in the synthesis of terpenoids that contribute to the scent profiles of flowers. However, few studies report the genome-wide analysis of <i>TPS</i>s gene in <i>Jasminum sambac</i> var. <i>Fuzhou bifoliatum</i> and their expression pattern in response to methyl jasmonate (MeJA). In this study, we employed bioinformatics tools for genome-wide analysis of the <i>J</i>. <i>sambac</i> TPS (DJTPS) gene family and determined the physical and chemical properties, subcellular location, protein-protein interactions, phylogenetic relationship, subfamily classification, chromosomal location and collinearity, gene structure, conserved motifs, and promoter <i>cis</i>-acting elements. The expression patterns of <i>DJTPS</i>s in different tissues and in response to MeJA treatment were analyzed based on the transcriptome data combined with quantitative real-time PCR (qRT-PCR). We identified 32 intact <i>DJTPS</i> genes in the genome of <i>J</i>. <i>sambac</i>, which presented uneven distribution across nine chromosomes. All the deduced proteins were hydrophilic, predominantly localized in the cytoplasm. The phylogenetic analysis classified the <i>DJTPS</i> genes into five subfamilies: TPS-a, TPS-b, TPS-c, TPS-e/f, and TPS-g. The results of the collinearity analysis showed a total of 10 sets of replication events in <i>DJTPS</i>s, most of which underwent purifying selection. A comparative analysis of <i>TPS</i> homologous gene pairs was performed among <i>J</i>. <i>sambac</i> var. <i>Fuzhou bifoliatum</i> and other six species, which revealed different number of homologous gene pairs. The number of exons and motifs was conserved within the same subfamily. <i>DJTPS</i> genes carried multiple elements that may be involved in the response to MeJA. In addition, the transcriptome and qRT-PCR data unveiled that several <i>TPS</i> genes exhibited tissue-specific expression patterns, and the genes with specific expression in flowers were the most. Upon exposure to MeJA, 14 <i>TPS</i> genes showcased upregulated expression 5 h or 6 h post-treatment, and <i>DJTPS03</i>, <i>DJTPS04</i> and <i>DJTPS21</i> showed significantly increased expression levels after MeJA treatment. This study provides preliminary evidence that MeJA possesses the ability to enhance the expression of <i>DJTPS</i> genes during the critical flowering stage, which will facilitate the synthesis of terpenoids and improve the quality of floral fragrance.