Function of in Flowering Induction in Two Species.

(), belonging to the / gene family, is an important gene regulating the flowering transition and inflorescence architecture during plant development. Given its importance to plant adaptation and crop improvement, has been extensively studied in related plant research; however, the specific role and underlying molecular mechanisms of in the continuous flowering of perennial plants remains elusive. Here, we isolated and characterized homologous genes from two species with different flowering-period phenotypes: was isolated from , a precious species blooming in summer and flowering throughout the year, and was isolated from , which blooms in winter and spring. The major difference in the genes between the two species was an additional five-amino acid repeat sequence in . showed high expression levels in the leaves in both species from January to August, especially in April for and in May for . was expressed throughout the year in , whereas was not expressed from September to December in . The expression levels of in the floral buds were generally higher than those in the leaves. Overexpression of and in indicated that both genes can activate downstream genes to promote flowering. Transgenic callus tissue was obtained by introducing the two genes into through -mediated transformation. Transcriptome and quantitative real-time polymerase chain reaction analyses indicated that both florigen genes promoted the expression of downstream genes such as , , and , and slightly up-regulated the expression of upstream genes such as and . The above results indicated that and played a role in promoting flowering in both camellia species. The expression pattern of in leaves suggested that, compared to may be related to the annual flowering of .