Molecular Mechanisms Underlying Flower Bud Differentiation in Osmanthus fragrans Lour

Osmanthus fragrans, an evergreen tree or shrub belonging to the Oleaceae family, is widely utilized in landscaping, food processing, and the fragrance industry for its unique aroma and ornamental values. Through natural and artificial selection, O. fragrans has diverged into two horticultural groups: the Asiaticus Group, which blooms year-round, and the Autumn Flowering Group, characterized by concentrated flowering in autumn. This phenotypic diversity is paramount importance for enhancing landscape value, extending the harvest periods, and meeting commercial demands. However, current research on flowering period differences among O. fragrans cultivars primarily focuses on physiological traits such as flower bud differentiation and phenological traits, with limited studies at the genetic and molecular levels. This article summarized the research progress in the classification characteristics, flower bud differentiation stages and processes, and the molecular mechanisms of flowering in O. fragrans, with a particular emphasis on the key genes that influence environmental factors such as high temperature, low temperature, and drought on the flowering period, and the regulatory mechanisms underlying the repeated flowering of the Asiaticus Group. The aim is to provide a theoretical foundation for breeding new cultivars with varied flowering times. Future research on O. fragrans will employ multi-omics technologies to systematically elucidate the key genes, signaling pathways, and epigenetic networks that regulate flower bud differentiation. A primary objective is to elucidate the synergistic interactions between environmental factors and endogenous hormones, thereby establishing precise models for flowering regulation and guiding practical production applications of O. fragrans.