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

Abstract

Ginkgo biloba has edible, medicinal, and ornamental value. However, the long juvenile phase prevents the development of the G. biloba industry, and there are few reports on the identification and functional analysis of genes regulating the flowering time of G. biloba. EMBRYONIC FLOWER 2 (EMF), an important protein in flower development, functions to promote vegetative growth and repress flowering. In this study, a novel EMF gene (GbEMF2) was cloned and characterized from G. biloba. GbEMF2 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 GbEMF2 was expressed in all detected organs, and it showed a significantly higher level in ovulating strobilus and microstrobilus than in other organs. Compared with emf2 mutant plants, overexpression of GbEMF2 driven by the CaMV 35S promoter in emf2 mutant Arabidopsis plants delayed flowering but earlier than wild-type (WT) plants. This result indicated that GbEMF2 repressed flowering in G. biloba. Moreover, the RNA-seq analysis of GbEMF2 transgenic Arabidopsis plants (GbEMF2-OE/emf2), WT plants, and emf2 mutants screened out 227 differentially expressed genes (DEGs). Among these DEGs, FLC, MAF5, and MAF5-1 genes were related to flower organ development and regulated by GbEMF2. In addition, some genes participating in sugar metabolism, such as Alpha-amylase 1 (AMY1), BAM1, and Sucrose synthase 3 (SUS3) genes, were also controlled by GbEMF2. Overall, our results suggested that GbEMF2 negatively regulates flowering development in G. biloba. This finding provided a foundation and target gene for shortening the Ginkgo juvenile period by genetic engineering technology.

Characterization of Phytohormones and Transcriptomic Profiling of the Female and Male Inflorescence Development in Manchurian Walnut (Juglans mandshurica Maxim.)

“…Sugar metabolism plays an important role in the reproductive development of plants and contributes to the formation of the cell wall, pollen maturation, and pollen tube growth [ 58 ]. During flower development, sugar metabolism and transport are relatively complex and include multiple biological processes such as synthesis, transport, and metabolism [ 59 , 60 ]. SUS and sucrose invertase (INV) are the two main enzymes that contribute to sucrose metabolism.…”

Cloning and functional analysis of Gb4CL1 and Gb4CL2 from Ginkgo biloba

“…The Gb4CL1 and Gb4CL2 were amplified and connected to pMD19‐T vector according to the method described by Zhou et al. (2021).…”

“…Primers for amplification of Gb4CL1 and Gb4CL2 were designed by online software (https://sg.idtdna.com/site/Order/oligoentry; Table S1). The Gb4CL1 and Gb4CL2 were amplified and connected to pMD19-T vector according to the method described by Zhou et al (2021).…”

Genomic and genetic advances of oiltea-camellia (Camellia oleifera)

“…Overexpression of CoFT1 in Arabidopsis leaded to precocious flowering possible by increasing the expression of flowering related genes, such as SOC1 , AP1 , and LFY ( Lei et al., 2017 ). EMF2 was found to inhibit flowering during plant development ( Chou et al., 2001 ; Zhou et al., 2021 ). Although the sequence of CoEMF2 identified in C. oleifera was highly conservative compared with EMF2 in other plants.…”