Functional Characterization of the EMBRYONIC FLOWER 2 Gene Involved in Flowering in Ginkgo biloba

has edible, medicinal, and ornamental value. However, the long juvenile phase prevents the development of the industry, and there are few reports on the identification and functional analysis of genes regulating the flowering time of . EMBRYONIC FLOWER 2 (EMF), an important protein in flower development, functions to promote vegetative growth and repress flowering. In this study, a novel gene ( ) was cloned and characterized from . contains a 2,193 bp open reading frame (ORF) encoding 730 amino acids. GbEMF2 harbors conserved VEFS-Box domain by the plant EMF protein. The phylogenic analysis showed that GbEMF2 originated from a polycomb-group (Pc-G) protein ancestor and was a member of the EMF2 protein. The quantitative real-time PCR (qRT-PCR) analysis revealed that was expressed in all detected organs, and it showed a significantly higher level in ovulating strobilus and microstrobilus than in other organs. Compared with mutant plants, overexpression of driven by the CaMV 35S promoter in mutant plants delayed flowering but earlier than wild-type (WT) plants. This result indicated that repressed flowering in . Moreover, the RNA-seq analysis of transgenic plants ( ), WT plants, and mutants screened out 227 differentially expressed genes (DEGs). Among these DEGs, , , and genes were related to flower organ development and regulated by . In addition, some genes participating in sugar metabolism, such as ( ), , and ( ) genes, were also controlled by . Overall, our results suggested that negatively regulates flowering development in . This finding provided a foundation and target gene for shortening the Ginkgo juvenile period by genetic engineering technology.