Genome-wide identification and expression analysis of the frigida domain gene family in Prunus mume ( Prunus mume Sieb. et Zucc.)

Frigida genes play a key role in regulating flowering time in plants. In this study, we identified 12 PmFRL genes and named them according to their chromosomal positions. These genes are unevenly distributed on five chromosomes. Phylogenetic analysis of Frigida-like proteins of four Rosaceae species and Arabidopsis thaliana showed that these proteins could be divided into five subfamilies (I–V), and subfamily I (FRI) was absent in Rosaceae species. To further reveal the potential functions of these proteins, we performed duplication analysis and found three tandem duplication events and one segmental duplication event. Tandem duplication promoted the expansion and evolution of the PmFRL genes. RNA-seq analysis showed that the PmFRL genes were expressed in different tissues, but there were significant differences in the expression of some genes during dormancy. RT-qPCR results supported the RNA-seq results, suggesting that PmFRL genes may be involved in the regulation of dormancy in Japanese apricot. In conclusion, our comprehensive analysis provides information on the evolution and possible functions of PmFRL genes, laying a foundation for further research on the PmFRL family.