Regulation of flowering time in Arabidopsis

 

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Flowering pathway

Gibberellin pathway

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The Gibberellin transduction pathway

 

EAF1 (EARLY FLOWERING 1)

 

The sequence gene function have not yet been characterized.

eaf1 mutants are early flowering:

eaf1 mutants have been isolated from a Ds insertion mutant population. Scott et al. (1999) identified the EAF1 locus. However, as no Ds insertion was found within the EAF1 gene in the eaf1 mutant, the origin of the mutant phenotype is not yet understood.

The eaf1 mutants flower early both in short days and in long days, but the effect is much more pronounced in short days. They respond like the WT to vernalization (Scott et al., 1999), so EAF1 does not seem to be involved in this particular pathway. In the mutants, both juvenile and adult vegetative phases are shorter than in the WT, but the mutation affects mostly the adult vegetative phase (Scott et al., 1999).

eaf1 mutants show an enhanced response to GAs:

These mutants have light green leaves, elongated petioles, and display an increased resistance to the GA-inhibitor Paclobutrazol, all of which indicate an enhanced response to GAs (Scott et al., 1999).

GA treatment further increases the phenotype of the eaf1 mutants, which shows that the response to GAs in the eaf1 mutants is actually not saturated (Scott et al., 1999).

As eaf1 is a recessive mutation, it might be a loss-of-function mutation. In that case, EAF1 would be a negative regulator of floral transition (Scott et al., 1999).