Abstract
We identified those mutants, related with two genes, FLORAISON TARDIVE1 (FLA1) and FLA2, that showed a late flowering phenotype (about three more leaves than wild type).
FLA1 is described as a C2 domain-containing protein with an enzymatic domain. FLA1 is expressed in leaves and flowers. fla1 mutants flowered late only in long day conditions (LD). This phenotype indicates that FLA1 belongs to the photoperiodic pathway. However, FLA1 expression is constant over the time. CO expression was not affected by mutation of FLA1 suggesting that FLA1 acts downstream of CO or in a CO-independant pathway inside the photoperiodic pathway.
FLA2 seems to have a transcriptional factor activity. FLA2 expression has been detected only in flowers. In both long and short day conditions (LD and SD), fla2-1 and fla2-4 were late-flowering. These observations indicate that FLA2 belongs to the autonomous pathway.
Moreover, fla2-1 mutation negatively regulates most of the autonomous pathway genes. fla2-1/flc double mutant flowered as early as flc mutant suggesting that FLA2 is upstream of FLC.
