A conserved role of SHORT VEGETATIVE PHASE (SVP) in controlling flowering time of Brassica plants

The control of flowering time in Brassica plants is an important approach for improving productivity, as vegetative tissues are not produced after the floral transition in Brassica plants. In order to determine the feasibility of modulating flowering time in Chinese cabbage plants, genes homologous to Arabidopsis SHORT VEGETATIVE PHASE (AtSVP) were isolated from spring-type and fall-type cultivars of Chinese cabbage plants, and their functions were determined. Their deduced amino acid sequences were 91-93% identical with that of AtSVP. The expression of BcSVP was ubiquitously detected, and was unaffected by vernalization. Constitutive BcSVP expression induced late flowering with additional floral defects. This delayed flowering was attributed to the repression of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). BcSVP expression under the control of the AtSVP promoter also resulted in the complementation of the svp mutation in Arabidopsis. These results indicate that BcSVP is a functional equivalent of AtSVP and also suggest that BcSVP may prove useful for the genetic manipulation of flowering time in Brassica plants.