Genome-wide identification and expression profile of the MADS-box gene family in Erigeron breviscapus

The MADS-box gene family encodes transcription factors with many biological functions that extensively regulate plant growth, development and reproduction. Erigeron breviscapus is a medicinal herb used widely in traditional Chinese medicine, and is believed to improve blood circulation and ameliorate platelet coagulation. In order to gain a detailed understanding of how transcription factor expression may regulate the growth of this potentially important medicinal plant, a genome-wide analysis of the MADS-box gene family of E. breviscapus is needed. In the present study, 44 MADS-box genes were identified in E. breviscapus and categorized into five subgroups (MIKC, M alpha, M beta, M gamma and M delta) according to their phylogenetic relationships with the Arabidopsis MADS-box genes. Additionally, the functional domain, subcellular location and motif compositions of the E. breviscapus MADS-box gene products were characterized. The expression levels for each of the E. breviscapus MADS-box (EbMADS) genes were analyzed in flower, leaf, stem and root organs, and showed that the majority of EbMADS genes were expressed in flowers. Meanwhile, some MADS genes were found to express high levels in leaf, stem and root, indicating that the MADS-box genes are involved in various aspects of the physiological and developmental processes of the E. breviscapus. The results from gene expression analysis under different pollination treatments revealed that the MADS-box genes were highly expressed after non-pollinated treatment. To the best of our knowledge, this study describes the first genome-wide analysis of the E. breviscapus MADS-box gene family, and the results provide valuable information for understanding of the classification, cloning and putative functions of the MADS-box family.