Cloning, Expression and Functional Study of OfCOR27 Gene in Osmanthus fragrans

Blooming time is an important basis for constructing plant landscapes. The short flowering period of <i>Osmanthus fragrans</i>, recognized as one of the ten traditional flowers in China, considerably constrains the further utilization of its resources. To clarify <i>O. fragrans</i> flowering regulation, this study focused on <i>OfCOR27</i>, conducting cloning, expression analysis, and functional verification to explore its effects on <i>O. fragrans</i> flowering time. A <i>COR27</i> phylogenetic tree was built across six species; <i>OfCOR27</i> physicochemical properties, conserved structures, and promoter cis-elements were analyzed. <i>OfCOR27</i> CDS was cloned, fusion vectors were transformed into <i>Nicotiana benthamiana</i>, and organ-specific expression was tested in two <i>O. fragrans</i> cultivars. Overexpression vectors were transformed into <i>Arabidopsis thaliana</i>, with qRT-PCR verifying gene function. Five <i>OfCOR27</i>s were identified, showing evolutionary conservation. <i>OfCOR27</i>, which localizes to the nucleus and is associated with flowering regulation, shows higher expression in 'Sijigui' than in 'XiaoyeSugui'. Overexpression of <i>OfCOR27</i> promoted flowering in <i>A. thaliana</i>, whereas the <i>AtCOR27</i> mutant flowered later. This confirms <i>OfCOR27</i> is a positive regulator of plant flowering, which may promote flowering by enhancing the expression of flowering-promoting genes and altering hormone levels, providing a theoretical basis and candidate gene for the genetic improvement of flowering traits in woody ornamental plants.