Cloning And Expression Of CmCO And CmFT Controlling The Flowering Time Of Chrysanthemum And Genetic Transformation

Chrysanthemum is China's traditional name, one of the world's four fresh cut flowers. Now through the light cycle adjust flowering technology production, and perennial supply of market. But because chrysanthemum is short-day plant, taken for the anniversary production in spring, summer and winter shading light supplement etc, better-acknowledged blooming do massive human, material and financial resources waste, restricted the chrysanthemum industry fast development. Through the study of the molecules of chrysanthemum flower development mechanism and flowering regulation, to cultivate a new light cycle is not sensitive chrysanthemum is of important theoretical and practical significance.The genes of CO (CONSTANS) and FT (FLOWERING LOCUS T), which related to flowering time were isolated from Chrysanthemum morflorium (Ramat.) Kitam.'Jinba'by RT-PCR and rapid amplification of cDNA ends (RACE), and named it CmCO (Genbank accession No.JF488070 ) and CmFT (Genbank accession No.JF488071 ) respectively. CmCO and CmFT encoded 382 and 174 amino acids respectively. Alignment analysis showed that CmCO protein had typical structures of CO homologous protein, including B-box1, B-box2, CCT domain and COOH region. The deduced amino acid sequence of CmFT contained FT-like protein's conserved motifs and two critical amino acid residues. Homologous analysis showed that the homology of CmCO compared with FaCO (Fragaria ananassa) was highest by 65.8%, and with PsCOL (Pisum sativum) and AtCO (Arabidopsis thaliana) were by 62.0% and 55.6% . The homology of CmFT compared with HaFT2 (Helianthus annuus) was highest by 93.7%, and with VvFT (Vitis vinifera) and with AtFT (Arabidopsis thaliana) were 85.1% and 74.0%. Evolutionary tree clustering analysis indicated that the genetic distances between CmCO protein and HaCOL (Helianthus annuus) and HaFT2 were the shortest respectively among others. RT-PCR analysis showed that expression of CmCO and CmFT in the leaves of chrysanthemum quantity is extremely low under long-day conditions, but under short-day conditions, CmCO expressed at initial stage of floral bud differentiation (I), then decreased at the stage of involucre primordial diferentiation (â…¢)followed by a quick rise. CmFT expressed followed by the CmCO expression, and then kept to high expression. The expression of CmCO and CmFT at the leaves, floral buds and stems of chrysanthemum at initial stage of floret primordial differentiation (IV) indicated that the expression of CmCO in the leaves of chrysanthemum was the highest, and it in the floral buds lower, and it in the stems lowest. The expression of CmFT in the floral buds was the highest, and in the leaves lower, and in the stems lowest. The results presumed that the expressions of CmCO and CmFT were related with flowering of chrysanthemum induced by photoperiods.We constructed CmCO justice expression vector, and the successful conversion chrysanthemum, transgenic plants under long-day, short-day conditions are performing CmCO genes that early flower, can promote the function of early flowering plants. The results of the study shows that CmCO gene is regulation plant flowering time important genes.