Genome-Wide Identification and Functional Characterization of LncRNA-mRNA Networks During Petal Opening and Senescence in Osmanthus fragrans

Osmanthus fragrans, a fragrant plant native to China, is extensively utilized in the food and cosmetics industries. However, its optimal harvest period spans only 2–3 days, restricting industrial utilization. Long non-coding RNAs (lncRNAs) have emerged as key regulators of plant growth, yet their roles in O. fragrans petal opening and senescence remain unexplored. Here, we performed high-throughput sequencing of O. fragrans petals across six developmental stages, generating a valuable transcriptomic resource. We identified 57,860 mRNAs and 2414 lncRNAs, including 6499 differentially expressed mRNAs (DEMs) and 494 differentially expressed lncRNAs (DELs). Co-expression and WGCNA analyses revealed key modules associated with petal opening (Turquoise module) and senescence (Blue module). The Blue module, significantly correlated with the S6 senescence stage, contained hub lncRNAs novel_00098659 and novel_00077227 co-expressed with multiple transcription factors and hormone signaling components, including 10 ERFs, OfEIN3, OfJAZ, and OfMYC2. Transient overexpression of novel_00077227 in tobacco accelerated leaf senescence in a hormone-dependent manner, with significant increases in electrolyte leakage and MDA content, and reductions in chlorophyll content and antioxidant enzyme activities. qRT-PCR analysis confirmed that novel_00077227 alters the expression of tobacco homologs of predicted target genes involved in ethylene, auxin, jasmonate, and ABA signaling pathways. This study provides a valuable transcriptomic resource of senescence-associated lncRNAs in O. fragrans and offers evidence for the potential involvement of a key candidate, novel_00077227, in hormone-associated senescence regulation. These findings provide a foundation for future functional studies and potential applications in extending flower longevity.