Overexpression of the MiAGL1 gene from mango promoted flowering in transgenic Arabidopsis

MADS-box genes play a vital role in the vegetative and reproductive growth of plants. In this study, a MiAGL1 gene was cloned and identified from mango (Mangifera indica L.). The DNA sequence of AGAMOUS-LIKE1 (MiAGL1) was 8741 bp in length, including a 723 bp open reading frame and encoding 241 amino acids. MiAGL1 belongs to the MADS-box family. This gene was expressed not only in vegetative tissues but also in floral organs, and the highest expression level was found in flowers. MiAGL1 was expressed in leaves at different floral developmental stages, but the peak appeared at the floral organ differentiation stage. MiAGL1 was present in the cell membrane and nucleus. Ectopic expression of MiAGL1 in Arabidopsis resulted in significant early flowering under long-day conditions. Overexpression of MiAGL1 resulted in abnormal flowering and silique morphology, such as a decrease or absence of petals, smaller petals, and shorter, bent or distorted capsules. The endogenous Arabidopsis thaliana flowering-related genes FT, AP1, and SEP were significantly upregulated, and AtSVP was downregulated in the transgenic lines. Therefore, our data showed that the MiAGL1 gene may play a crucial role in flowering time regulation and floral organ identity.