Song YH, Lee I, Lee SY, Imaizumi T, Hong JC

Plants monitor changes in day length to coordinate flowering with favorable seasons to increase their fitness. The day-length specific induction of FLOWERING LOCUS T (FT) regulated by CONSTANS (CO) is the crucial aspect of photoperiodic flowering in Arabidopsis thaliana. Recent studies elucidated some mechanisms of CO-dependent FT induction. Here, we ...

Read More

demonstrate another mechanism of CO-dependent FT regulation. Our results indicate that CO protein regulates FT transcription partially by forming a complex with ASYMMETRIC LEAVES 1 (AS1) protein, which regulates leaf development partly by controlling gibberellin (GA) levels. We identified AS1 as a CO-interacting protein in yeast and verified their interaction in vitro and in planta. We also showed that the AS1 temporal and spatial expression pattern overlapped with that of CO. In addition, as1 mutants showed GA-independent delayed flowering under different light/dark conditions. FT expression levels in the as1 mutants and the SUC2:CO-HA/as1 line under long-day and 12-h light/12-h dark conditions were reduced compared to wild-type plants and the SUC2:HA-CO line, respectively. Moreover, AS1 directly bound to the specific regions of the FT promoter in vivo. These results indicate that CO forms a functional complex with AS1 to regulate FT expression and that AS1 plays different roles in two regulatory pathways, both of which concomitantly regulate a precise timing of flowering. © 2011 The Authors. The Plant Journal© 2011 Blackwell Publishing Ltd.

Date: Sep. 23, 2011

View in: Pubmed Google Scholar

124163