RT Journal Article
SR Electronic
T1 GA<sub>4</sub> Is the Active Gibberellin in the Regulation of <em>LEAFY</em> Transcription and <em>Arabidopsis</em> Floral Initiation
JF The Plant Cell
JO Plant Cell
FD American Society of Plant Biologists
SP 2172
OP 2181
DO 10.1105/tpc.106.042317
VO 18
IS 9
A1 Eriksson, Sven
A1 Böhlenius, Henrik
A1 Moritz, Thomas
A1 Nilsson, Ove
YR 2006
UL http://www.plantcell.org/content/18/9/2172.abstract
AB Flower initiation in Arabidopsis thaliana under noninductive short-day conditions is dependent on the biosynthesis of the plant hormone gibberellin (GA). This dependency can be explained, at least partly, by GA regulation of the flower meristem identity gene LEAFY (LFY) and the flowering time gene SUPPRESSOR OF CONSTANS1. Although it is well established that GA4 is the active GA in the regulation of Arabidopsis shoot elongation, the identity of the GA responsible for the regulation of Arabidopsis flowering has not been established. Through a combination of GA quantifications and sensitivity assays, we show that GA4 is the active GA in the regulation of LFY transcription and Arabidopsis flowering time under short-day conditions. The levels of GA4 and sucrose increase dramatically in the shoot apex shortly before floral initiation, and the regulation of genes involved in GA metabolism suggests that this increase is possibly due to transport of GAs and sucrose from outside sources to the shoot apex. Our results demonstrate that in the dicot Arabidopsis, in contrast with the monocot Lolium temulentum, GA4 is the active GA in the regulation of both shoot elongation and flower initiation.