Molecular cloning of SVP: a negative regulator of the floral transition inArabidopsis

Flowering time mutants represent genetic functions in control of the floral transition, an important developmental phase switch in the life cycle of h igher plants. Many such mutants have been identified and characterized, par ticular in Arabidopsis. Here we describe the identification and initial cha racterization of a new early flowering mutant of Arabidopsis. The correspon ding gene, SVP (SHORT VEGETATIVE PHASE), was cloned through transposon tagg ing and represents a new member of the MADS-box gene family of transcriptio n factors. Analysis of its transcriptional activity revealed the presence o f differently sized transcripts that were confined to vegetative tissues an d floral primordia and absent from developed flowers and siliques. The func tion of SVP as a repressor of the floral transition is discussed.