Abstract
Arabidopsis MADS-box genes, AGL24 and SVP are phylogenetically very close, while AGL24 promotes flowering, SVP represses it. Both genes encode transcription factors which consist of MADS-box, I, K, and C domains. To investigate the mode of action of AGL24 and SVP proteins, we tried to identify the domains responsible for their functional specificities. We generated and analyzed transgenic plants constitutively overexpressing chimeric AGL24 and SVP genes. As a result, plants carrying the construct which contains the SVP MADS-box and the AGL24 I, K, and C flowered earlier than wild type. In contrast, plants with the construct which contains the AGL24 MADS-box and SVP I, K, and C showed a late flowering phenotype. These results indicates that I, K, and C domains are important for the regulation of flowering, suggesting that differences in the formation of higher-order complexes between AGL24 and SVP may determine their functional specificities.
