Abstract
Arabidopsis AGL24 encodes a MADS-box transcription factor, and it promotes flowering. A second MADS-box gene SVP, which is phylogenetically very close to AGL24, represses flowering. In this study we focused on the target genes of AGL24 and SVP to understand the mechanisms of their transcriptional regulation. To identify their downstream genes microarray experiments were performed using shoot apices of agl24 and svp mutants and transgenic plants constitutively overexpressing AGL24 or SVP. Results indicated that 56 genes in AGL24-overexpressing plants, 171 in SVP-overexpressing plants, 7 in agl24, and 3 in svp were up- or down-regulated at least 2-fold compared to wild type. Most of them were not previously identified as having roles in flowering except for SOC1, a flowering pathway integrator. SOC1 expression increased in AGL24-overexpressing plants and svp, but decreased in SVP-overexpressing plants. These results suggest that AGL24 and SVP may antagonistically control flowering partly through the regulation of SOC1.
