Fig. 1. Generation of a functional estradiol-inducible AGL24 expression system. (A) Induction of AGL24 expression in 9-day-old pER22-AGL24 Arabidopsis seedlings mock-treated (M) or treated with 10 µM β-estradiol (E) for 0, 1, 2, 4, 8, 12 or 24 hours. TUB2 expression was used as a control. (B) The estradiol-inducible AGL24 system is biologically functional. The pER22-AGL24 plants (right) initially treated with β-estradiol at 9 days after germination show earlier flowering than mock-treated plants (left). (C) Upregulation of AGL24 during floral transition is sufficient to promote flowering. β-estradiol treatment did not affect the flowering of wild-type plants, whereas initial treatment of pER22-AGL24 with β-estradiol before or at the floral transitional stage (3, 6 or 9 days after germination) accelerated flowering.