Grapevine (Vitis vinifera) is an important and popular perennial fruit tree cultivated worldwide. Grapevine ripening is affected by flowering time, and although members of the MADS-box protein family play vital roles in regulating flowering in plants, the functions of MADS-box proteins in grapevine remain largely unknown. AGAMOUS-LIKE 11 (VvAGL11), a MADS-box gene in grapevine, was reported to be a regulator of seed morphogenesis. In this study, heterologous overexpression of VvAGL11 was found to significantly promote flowering in Arabidopsis, suggesting that its active expression in grapevine may induce early flowering and ripening. Transcriptome analysis showed that VvAGL11 overexpression affected the expression of genes involved in stress responses, hormonal signaling responses, and flowering regulation. Notably, VvAGL11 significantly increased the expression of key flowering genes such as FLOWERING LOCUS T (FT), APETALA3 (AP3), and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 5 (SPL5), which might have contributed to the early flowering in Arabidopsis. In summary, we characterized a novel flowering regulator, VvAGL11, which could be a potential target for early ripening breeding in grapevine.
