Identification and Characterization of MADS-box Genes Involved in Floral Organ Development in Chinese Chestnut (Castanea mollissima Blume)

Chinese chestnut (Castanea mollissima) is a woody plant species with important economic and ecological value and is widely cultivated for nut production. Due to its unique flowering structure, the identification of genes related to flower development is extremely important in Chinese chestnut, and MADS-box genes are directly involved in floral organ morphogenesis. In this study, we report a MADS-box gene family in Chinese chestnut. According to their gene structure and phylogenetic trees, 53 CmMADS proteins were identified and clustered into five groups in Chinese chestnut. The MIKCc group was further divided into 12 subgroups, and the BS subgroup was not found in Chinese chestnut. The classification and motif composition of Chinese chestnut MADS proteins were also analyzed. Additionally, we evaluated the expression of all the MADS-box genes in floral organs by quantitative real-time PCR. Overall, most of the type II genes had higher expression levels in the floral organs compared with leaves and cotyledons. These results provide valuable information for future studies of the regulation of MADS-box genes in Chinese chestnut during flower development.