Acceleration of flowering by overexpression of MFT (MOTHER OF FT AND TFL1).

MFT (MOTHER OF FT AND TFL1) is a member of a gene family that includes two important regulators, FT (FLOWERING LOCUS T) and TFL1 (TERMINAL FLOWER 1), in determination of flowering time in Arabidopsis. Although the functions of FT and TFL1 are assigned in the family, the roles of other members are largely unknown. Especially the sequence of MFT is homologous to both FT and TFL1, which act as a floral promoter and an inhibitor, respectively, making it difficult to predict the role of MFT. We performed genetic analyses of MFT to understand its role in floral development. Constitutive expression of MFT led to slightly early flowering under long days. However, a T-DNA insertion allele of MFT did not show obvious phenotype. Further genetic analyses with the loss-of-function alleles of FT, TFL1, and ATC (Arabidopsis Thaliana CENTRORADIALIS homologue) showed that a decrease of MFT activity did not enhance the phenotypes of the single mutants. Taken together, we suggest that MFT functions as a floral inducer and that it may act redundantly in determination of flowering time in Arabidopsis.