OfERF106-OfACS2 regulatory module helps accelerate the aging process of Osmanthus fragrans petals

OfERF106 protein binds to the promoter region of the ethylene biosynthesis gene OfACS2 and activates its expression, thereby accelerating the aging process of Osmanthus fragrans petals. Osmanthus fragrans is a multipurpose ornamental plant that combines landscaping utility, aesthetic appeal, and aromatic fragrance, granting it considerable economic and horticultural value. However, its value is substantially constrained by the short overall flowering period and the brief longevity of individual petals. The key regulatory genes, their functions, and the molecular mechanisms underlying petal senescence in O. fragrans remain largely unknown. Here, we identified a critical gene, OfERF106, from transcriptomic data. The expression level of OfERF106 peaked at the flower fading stage and was significantly higher than that observed during the primary and full blooming stages. The full-length sequence of OfERF106 contains a 675 bp open reading frame encoding 225 amino acids. Subcellular localization analysis confirmed that OfERF106 protein is localized in the nucleus. Overexpression of OfERF106 in Arabidopsis thaliana resulted in a flowering period shortened by 3-4 days compared to the control, indicating its role in promoting petal senescence. The functional validation of OfERF106 through rapid overexpression and silencing in O. fragrans petals further supported this result. Moreover, the expression levels of two ethylene biosynthesis-related genes (OfACS1 and OfACS2) were also significantly altered. Further analysis using yeast one-hybrid (Y1H) and dual luciferase (DLR) assays demonstrated that OfERF106 protein binds to the promoter of OfACS2 and activates its expression. These results suggest that OfERF106 accelerates petal senescence in O. fragrans by enhancing OfACS2 expression, which in turn promotes ethylene biosynthesis. Our study provides preliminary insights into the molecular mechanism regulating petal senescence in O. fragrans and highlights the functional role of OfERF106 in this process.