Genome-Wide Identification and Characterization of Long Non-Coding RNAs Associated with Floral Scent Formation in Jasmine (Jasminum sambac)

Long non-coding RNAs (lncRNAs) have emerged as curial regulators of diverse biological processes in plants. Jasmine (Jasminum sambac) is a world-renowned ornamental plant for its attractive and exceptional flower fragrance. However, to date, no systematic screening of lncRNAs and their regulatory roles in the production of the floral fragrance of jasmine flowers has been reported. In this study, we identified a total of 31,079 novel lncRNAs based on an analysis of strand-specific RNA-Seq data from J. sambac flowers at different stages. The lncRNAs identified in jasmine flowers exhibited distinct characteristics compared with protein-coding genes (PCGs), including lower expression levels, shorter transcript lengths, and fewer exons. Certain jasmine lncRNAs possess detectable sequence conservation with other species. Expression analysis identified 2752 differentially expressed lncRNAs (DE_lncRNAs) and 8002 DE_PCGs in flowers at the full-blooming stage. DE_lncRNAs could potentially cis- and trans-regulate PCGs, among which DE_lincRNAs and their targets showed significant opposite expression patterns. The flowers at the full-blooming stage are specifically enriched with abundant phenylpropanoids and terpenoids potentially contributed by DE_lncRNA cis-regulated PCGs. Notably, we found that many cis-regulated DE_lncRNAs may be involved in terpenoid and phenylpropanoid/benzenoid biosynthesis pathways, which potentially contribute to the production of jasmine floral scents. Our study reports numerous jasmine lncRNAs and identifies floral-scent-biosynthesis-related lncRNAs, which highlights their potential functions in regulating the floral scent formation of jasmine and lays the foundations for future molecular breeding.