Fig. 4. Reduction of FLC expression in bri1 ld, bri1 fca and bri1 FRI double mutants efficiently accelerates flowering. (A) The effect of vernalization treatment on flowering time in the following mutants: bri1-201, ld-3, fca-11, FRI in the Ws background, bri1-201 ld-3, bri1-201 fca-11 and bri1-201 FRI. Germinated seedlings were vernalized for 6 weeks under short days (8 hours light/16 hours darkness) at 4°C, after which they were grown under the same long-day conditions as control non-vernalized plants. White bars, non-vernalized controls; black bars, vernalization treatments. Absolute (B) and relative (C) FLC mRNA levels before (-; white bars) and after (+; black bars) vernalization. (D) Flowering phenotypes of four independent FLC-RNAi transgenic lines in the bri1-201 ld-3 double-mutant background, compared to two independent lines of bri1-201 ld-3 double mutants transformed with a control vector. 7-week-old plants are shown. (E) Flowering-time analysis of FLC-RNAi bri1 ld mutants grown under a long-day photoperiod. A representative result is shown. (F) RNA-blot analysis of FLC mRNA levels in 20-day-old FLC-RNAi bri1 ld mutants compared to the control bri1 ld lines. The ACT1 gene was used as a loading control.