Identification and expression analysis of the Cyclamen persicum MADS-box gene family

Molecular analysis of cyclamen flower architecture has not been widely performed, therefore effective molecular breeding of this plant is not available. The ABCDE model is based on interactions between members of different classes of transcription factors that establish floral organ identity, most of which belong to the MADS-box family. To elucidate the mechanism involved in regulating cyclamen flower development, we isolated genes encoding putative MADS-box transcription factors and analyzed their expression patterns in cyclamen. We cloned full-length cDNAs using homology-based RT-PCR and RACE-PCR, and identified and characterized 10 putative cyclamen MADS-box genes. A phylogenetic tree reveals that these genes are related to the APETALA1, PISTILLATA, APETALA3, AGAMOUS, SEEDSTICK, and SEPALLATA transcription factor subfamilies. Respective genes are expressed in each whorl according to the ABCDE function, but there are slight differences in the expression of several genes in various tissues; class-A homologous gene CpAP1 is not expressed in petal. One of three identified class-B homologous gene is TM6-like but expressed broadly. Two closely related class-C homologous genes are differentially expressed in stamens and carpels. These data suggest that modified ABC model might uniquely evolved in cyclamen.