GhAGL80–9 positively regulates flowering by activating the expression of GhAP1-D3 and GhAGL9 in Gossypium hirsutum L.

MADS-box transcription factors are significant flowering regulators of plants. However, whether and how GhAGAMOUS-LIKE 80–9 (GhAGL80–9), a MADS-box protein, modulates flowering in Gossypium hirsutum L. (cotton) is unclear. In this study, GhAGL80–9 was demonstrated to locate in the nucleus and have transcriptional activity. Moreover, cotton plants with silenced GhAGL80–9 caused by virus-induced gene silencing (VIGS) showed clearly late flowering compared with the controls. Overexpression of GhAGL80–9 in Arabidopsis thaliana L. wild type plants led to notably accelerated flowering. GhAGL80–9 could also bind to the promoters of GhAPETALA1-D3 ( GhAP1-D3 ) and GhAGL9 , and stimulated their expression. Additionally, VIGS cotton plants silencing GhAGL9 exhibited markedly delayed flowering. Together, these results suggest that GhAGL80–9 positively regulates flowering through promoting the transcription of GhAP1-D3 and GhAGL9 in cotton plants. • GhAGL80–9 positively regulates flowering in cotton. • GhAGL80–9 could bind to the promoters of GhAP1-D3 and GhAGL9 . • Silencing GhAGL9 delays the flowering of cotton.