GmMADS66 regulates flowering time under photoperiod dependent pathway in Arabidopsis

Flowering time is an essential factor for soybean production, and the MADS-box gene family members play an important role in the regulation of plant development and flowering time. In this study, we identified a member of the MADS-box transcription factor family, GmMADS66. Phylogenetic analysis showed that GmMADS66 was a homologous gene of the SOC1-like subfamily genes AtAGL14 and AtAGL19 . GmMADS66 showed highest expression levels in trifoliate leaves, and also accumulated in shoot apical meristems before flowering. Meanwhile, the expression of GmMADS66 increased during the day, and decreased in the dark under both long-day and short-day conditions. Subcellular localization analysis exhibited that GmMADS66 was located in the nucleus. Furthermore, overexpression of GmMADS66 induced early flowering in Arabidopsis under both long-day and short-day conditions. Transcriptome analysis and interacting proteins prediction revealed that GmMADS66 induced early flowering in Arabidopsis under long-day and short-day through different pathways. Our study is important for further understanding the function of GmMADS66 in flowering time regulation and providing genetic resources for targeted improvement of widely adaptable soybean varieties. Key message Overexpression of soybean MADS-box gene GmMADS66 accelerates flowering time in Arabidopsis under both long-day and short-day conditions by regulating different downstream genes.