Identification of MBW Complex Components Implicated in the Biosynthesis of Flavonoids in Woodland Strawberry

Abstract

Flavonoids belong to the family of polyphenolic secondary metabolites and contribute to fruit quality traits. It has been shown that MBW complexes (MYB-bHLH-WD40) regulate the flavonoids biosynthesis in different plants, but only a limited number of MBW complexes have been identified in strawberry species in general. In this study, we identified 112 R2R3-MYB proteins in woodland strawberry; 12 of them were found to have potential functions in regulating flavonoids biosynthesis by phylogenetic analysis. qRT-PCR assays showed that FvMYB3, FvMYB9, FvMYB11, FvMYB22, FvMYB64, and FvMYB105 mostly expressed at green stage of fruit development, aligned with proanthocyanidins accumulation; FvMYB10 and FvMYB41 showed higher expression levels at turning and ripe stages, aligned with anthocyanins accumulation. These results suggest that different MYBs might be involved in flavonoids biosynthesis at specific stages. Furthermore, FvMYB proteins were demonstrated to interact with FvbHLH proteins and induce expression from the promoters of CHS2 and DFR2 genes, which encode key enzymes in flavonoids biosynthesis. The co-expression of FvMYB and FvbHLH proteins in strawberry fruits also promoted the accumulation of proanthocyanidins. These findings confirmed and provided insights into the biofunction of MBW components in the regulation of flavonoid biosynthesis in woodland strawberry.

Integrative Analysis of Metabolome and Transcriptome Identifies Potential Genes Involved in the Flavonoid Biosynthesis in Entada phaseoloides Stem

“…The previous research showed that many MBW complexes are involved in regulating flavonoid synthesis ( Ramsay and Glover, 2005 ; Xu et al, 2015 ; Xu et al, 2021 ). In this study, the expression of 47 genes encoding MYB, bHLH, and TRANSPARENT TESTA GLABRA 1 (TTG1) homologs was highly correlated with the amount of 81 flavonoids, including 32 MYBs, 13 bHLHs, and 2 TTG1 homologs ( Supplementary Table 13 ).…”

Integrated analysis of multi-omics and fine-mapping reveals a candidate gene regulating pericarp color and flavonoids accumulation in wax gourd (Benincasa hispida)

“…The co-expression plot also indicated the co-expression of 6LHCA6 , MYB1R1 , and WD40 with the hub gene BhiPRR6 . Among them, MYB-bHLH-WD40 ternary complex (MBW complex) is a typical representative to positively regulate the biosynthesis of anthocyanins and flavonoids ( Xu et al., 2021 ). The expression pattern of the co-expressed genes showed consistency with that of BhiPRR6 and its associated target genes, indicating that they are similarly regulated in this hfc12 ( Figure S2 ).…”

Anthocyanins as Key Phytochemicals Acting for the Prevention of Metabolic Diseases: An Overview

“…The enzymes involved in the final part of the synthesis, also known as late flavonoid biosynthesis genes (LBGs) such as DRF, ANS, and UFGT, as well as the membrane tonopast transporters, ABC and MATE, are activated by the upregulation of the ternary complex MBW (R2R3-MYB, bHLH, and WD40) [38]. The MBW family of transcription factors is considered to be crucial in the biosynthesis of ANs and has been identified in ripened fruits such as woodland strawberries, in large quantities, especially the R2R3-MYB protein [39]. MYB genes that belong to the MBW have also been associated with proanthocyanins production in strawberries, as FvMYB3, FvMYB9, FvMYB11, FvMYB22, FvMYB64, and FvMYB105 genes were expressed especially in the green stage of the strawberries development, which highlights the involvement of the MBW complex in different stages of ripening of the fruits [39].…”

“…The MBW family of transcription factors is considered to be crucial in the biosynthesis of ANs and has been identified in ripened fruits such as woodland strawberries, in large quantities, especially the R2R3-MYB protein [39]. MYB genes that belong to the MBW have also been associated with proanthocyanins production in strawberries, as FvMYB3, FvMYB9, FvMYB11, FvMYB22, FvMYB64, and FvMYB105 genes were expressed especially in the green stage of the strawberries development, which highlights the involvement of the MBW complex in different stages of ripening of the fruits [39]. Moreover, the MBW complex was also observed to participate in the activation of the EBGs in some cases such as corn (Zea mays) [40].…”