Regulation of flowering time in Arabidopsis



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Flowering pathway

Gibberellin pathway



The Gibberellin transduction pathway


FPF1 depends on GA biosynthesis


FPF1 expression depends on the GA biosynthesis pathway:

Plants over-expressing FPF1 in the WT background flower early. In several late-flowering mutants not affected in the GA transduction pathway (fca-1, fve-1, co-2, gi-3 and fwa-1), over-expression of FPF1 also accelerates flowering (Melzer et al., 1999). However, over-expression of FPF1 cannot accelerate flowering in the GA-deficient ga1-2 mutants. The early flowering associated with FPF1 over-expression  may be due to an increased synthesis of GAs, but it is more probable that it is due to an enhanced responsiveness to GAs (Kania et al., 1997).

FPF1 acts only within the GA transduction pathway:

The over-expression of FPF1 leads to an early-flowering phenotype that is mostly independent of the photoperiod (Melzer et al., 1999). Plants constitutively expressing FPF1 are unable to flower in short days if they have been treated with the GA inhibitor Paclobutrazol. This means that FPF1 regulates flowering time only within the GA transduction pathway (Kania et al., 1997).

FPF1 expression is not modified in the fca-1, co-2, gi-3, fve-1 and fwa-1 mutants. This means that these genes (and the pathways that regulate their expression) are independent of FPF1 (Melzer et al., 1999).