Genome-Wide Identification and Expression Analysis of MIKC-Type MADS-Box Gene Family in Punica granatum L.

MADS-box is a critical transcription factor regulating the development of floral organs and plays essential roles in the growth and development of floral transformation, flower meristem determination, the development of male and female gametophytes, and fruit development. In this study, 36 MIKC-type MADS-box genes were identified in the 'Taishanhong' pomegranate genome. By utilizing phylogenetic analysis, 36 genes were divided into 14 subfamilies. Bioinformatics methods were used to analyze the gene structure, conserved motifs,cis-acting elements, and the protein interaction networks of the MIKC-type MADS-box family members in pomegranate, and their expressions pattern in different tissues of pomegranate were analyzed. Tissue-specific expression analysis revealed that the E-class genes (PgMADS03,PgMADS21,andPgMADS27) were highly expressed in floral tissues, whilePgMADS29was not expressed in all tissues, indicating that the functions of the E-class genes were differentiated.PgMADS15of the C/D-class was the key gene in the development network of pomegranate flower organs, suggesting thatPgMADS15might play an essential role in the peel and inner seed coat development of pomegranate. The results in this study will provide a reference for the classification, cloning, and functional research of pomegranate MADS-box genes.