Functional Diversification of the Dihydroflavonol 4-Reductase from Camellia nitidissima Chi. in the Control of Polyphenol Biosynthesis

Abstract

Plant secondary metabolism is complex in its diverse chemical composition and dynamic regulation of biosynthesis. How the functional diversification of enzymes contributes to the diversity is largely unknown. In the flavonoids pathway, dihydroflavonol 4-reductase (DFR) is a key enzyme mediating dihydroflavanol into anthocyanins biosynthesis. Here, the DFR homolog was identified from Camellia nitidissima Chi. (CnDFR) which is a unique species of the genus Camellia with golden yellow petals. Sequence analysis showed that CnDFR possessed not only conserved catalytic domains, but also some amino acids peculiar to Camellia species. Gene expression analysis revealed that CnDFR was expressed in all tissues and the expression of CnDFR was positively correlated with polyphenols but negatively with yellow coloration. The subcellular localization of CnDFR by the tobacco infiltration assay showed a likely dual localization in the nucleus and cell membrane. Furthermore, overexpression transgenic lines were generated in tobacco to understand the molecular function of CnDFR. The analyses of metabolites suggested that ectopic expression of CnDFR enhanced the biosynthesis of polyphenols, while no accumulation of anthocyanins was detected. These results indicate a functional diversification of the reductase activities in Camellia plants and provide molecular insights into the regulation of floral color.

Overexpression of dihydroflavonol 4-reductase (CoDFR) boosts flavonoid production involved in the anthracnose resistance

“…Therefore, the GFP fluorescence observed in the membrane could be attached to the endoplasmic reticulum ( Voeltz et al., 2002 ). Another possibility is that CoDFR an extremely likely dual subcellular localization ( Jiang et al., 2020 ). To further explore the function of CoDFR , we generated transgenic tobacco plants overexpressing CoDFR .…”

“…Dihydroflavonol 4-reductase (DFR) is a key enzyme in the flavonoid pathway for the synthesis of anthocyanins, catechins, and procyanidins ( Tian et al., 2017 ). It controls the flux of each branch pathway for the production of these three substances ( Punyasiri et al., 2004 ; Jiang et al., 2020 ; Ruan et al., 2022 ). The DFR genes have been cloned and identified in most plants, for example, Ipomoea batatas Lam.…”

Comparative Transcriptome Analysis Identifies Key Regulatory Genes Involved in Anthocyanin Metabolism During Flower Development in Lycoris radiata

“…Among them, DFR catalyzes the conversion of dihydroflavonols to leucoanthocyanidins, which is one of the final stages of anthocyanin biosynthesis ( Shimada et al, 2005 ; Luo et al, 2016 ). DRF gene is responsible for plant pigmentation ( Lou et al, 2014 ), and its mutation has been associated with the loss of anthocyanins as well as proanthocyanidins ( Liu H. et al, 2019 ; Jiang et al, 2020 ; Lim et al, 2020 ; Feng et al, 2021 ). Besides, enhancement or activation of DFR gene expression is vital in MYB transcription factor (TF)-based anthocyanin engineering.…”

Elevated CO2 concentration induces changes in plant growth, transcriptome, and antioxidant activity in fennel (Foeniculum vulgare Mill.)

“…S-adenosyl-L-methionine-dependent methyltransferases reportedly play important roles in flavonoid-related metabolic pathways (Joshi and Chiang, 1998). The high expression levels of dihydroflavonol 4-reductase, a key enzyme involved in anthocyanin biosynthesis, resulted in an increase in the TFC in Camellia transgenic lines (Jiang et al, 2020). Flavonoid synthase overexpression led to flavonoid accumulation as well as the suppression of anthocyanin synthesis in Crabapples (Tian et al, 2015).…”