Ectopic Expression of MADS-Box Transcription Factor VvAGL12 from Grape Promotes Early Flowering, Plant Growth, and Production by Regulating Cell-Wall Architecture in Arabidopsis

The MADS-box family, a substantial group of plant transcription factors, crucially regulates plant growth and development. Although the functions of AGL12-like subgroups have been elucidated in Arabidopsis, rice, and walnut, their roles in grapes remain unexplored. In this study, we isolated VvAGL12, a member of the grape MADS-box group, and investigated its impact on plant growth and biomass production. VvAGL12 was found to localize in the nucleus and exhibit expression in both vegetative and reproductive organs. We introduced VvAGL12 into Arabidopsis thaliana ecotype Columbia-0 and an agl12 mutant. The resulting phenotypes in the agl12 mutant, complementary line, and overexpressed line underscored VvAGL12’s ability to promote early flowering, augment plant growth, and enhance production. This was evident from the improved fresh weight, root length, plant height, and seed production, as well as the reduced flowering time. Subsequent transcriptome analysis revealed significant alterations in the expression of genes associated with cell-wall modification and flowering in the transgenic plants. In summary, the findings highlight VvAGL12′s pivotal role in the regulation of flowering timing, overall plant growth, and development. This study offers valuable insights, serving as a reference for understanding the influence of the VvAGL12 gene in other plant species and addressing yield-related challenges.