FLOWERING LOCUS T (FT) in Photosensitive Type Chrysanthemum Accelerates Flowering in Arabidopsis

FLOWERING LOCUS T (FT) is an important factor for integrating flowering signals through the photoperiod pathway, which significantly promotes flowering. Most chrysanthemum varieties are short-day plants, sensitive to the photoperiod, which limits their ornamental and annual production supply. In this study, we aim to analyze the nutrients and flowering-related genes of chrysanthemums with different photoperiod types and to clone and verify the function of the flowering-related gene CmFT. We found that the formation of floral buds requires the accumulation of starch while consuming soluble sugars and the expression patterns of flowering-related genes GIGANTEA (GI), CONSTANS (CO), and FT in C.morifolium ‘Zilian’ and C. morifolium ‘Zihongtuogui’ had a certain synchronization during floral buds differentiation according to our quantitative validation, and the expression levels of CmGI, CmCO and CmFT in C. morifolium ‘Zihongtuogui’ were higher than those in C. morifolium. ‘Zilian’ in the later stage of differentiation. CmFT was cloned from photosensitive chrysanthemums-C. morifolium ‘Zihongtuogui’ and polypeptide alignment and phylogenetic analysis showed that CmFT was clustered in FT-like subfamily. In further functional verification, we obtained two Arabidopsis transgenic lines. Our results showed that CmFT transgenic ft mutant lines can significantly accelerate flowering in Arabidopsis. Thus, we can initially confirm that CmFT plays an important role in promoting flowering, which may be the key reason for the photosensitivity of C. morifolium ‘Zihongtuogui’. Overall, the results of this study are of great importance in revealing the flowering mechanism of different photoperiod types of chrysanthemums.