Functional studies of four MiFPF genes in mango revealed their function in promoting flowering in transgenic Arabidopsis

Flowering promoting factor (FPF) genes play a substantial regulatory role in the process of flowering. In the present study, four MiFPF genes, namely, MiFPF1, MiFPF2, MiFPF3a, and MiFPF3b, were obtained from mango (Mangifera indica L.). Tissue expression analysis showed that MiFPFs were expressed in all mango tissues. Specifically, MiFPF1 and MiFPF2 were highly expressed in leaves, while MiFPF3a and MiFPF3b were highly expressed in flowers and buds. The four MiFPF proteins localize to the nucleus. Overexpression of MiFPFs in transgenic Arabidopsis resulted in early flowering and upregulated the expression of APETAL1 (AP1), FLOWERING LOCUS D (FD) and FLOWERING LOCUS T (FT). MiFPF genes increased the root growth of transgenic Arabidopsis plants under gibberellin treatment. BiFC assays showed that MiFPFs can interact with several DELLA proteins. Taken together, our results demonstrate that the MiFPF gene was involved not only in promoting flowering but also in increasing root growth under gibberellin (GA3) treatment.