Meta-Analysis of the Effect of Overexpression of MYB Transcription Factors on the Regulatory Mechanisms of Anthocyanin Biosynthesis

Abstract

MYBs (v-myb avian myeloblastosis viral oncogene homologs) are important transcriptional regulators that play critical roles in the regulation of anthocyanin biosynthesis. The overexpression of MYB genes has been reported in different plant species. However, the inconsistent strategies to assess transgenic plants have made it difficult to explain the complex mechanisms of regulation of anthocyanin biosynthesis by MYBs. We report here a meta-analysis of 608 studies from 206 publications assessing the effects of MYB overexpression on anthocyanins and evaluate the experimental variables that have an influence on transgenic plant performance. We found that MYB expression enhanced the magnitude of 20 out of 26 examined plant parameters by at least of 21% and reduced the magnitude of 1 indicator by at least 37%. We explored the variety of moderating variables causing these variations. A deeper color induced by MYBs caused higher plant attributes as compared to normal color changes. MYB genes from dicots stimulated the accumulation of anthocyanins, flavonols and impacted the expressions of PAL, CHS, CHI, FLS, F3′5′H, ANS, UFGT, and ANR as compared to monocots. Heterologous expression and homologous expression showed a great difference in anthocyanin biosynthesis. Transient gene transformation had a significant effect on the expression of flavonoid biosynthetic genes, and stable transformation had a significant effect on flavonoid accumulation. Stress could result in a significantly increased accumulation of flavonoids, especially anthocyanin, flavonol, and proanthocyanidin. Our study, thus, provides new insights into the function of MYBs in the regulatory mechanisms of flavonoid biosynthesis and the use of genetic engineering for improving anthocyanins contents.

Metabolomic and transcriptomice analyses of flavonoid biosynthesis in apricot fruits

“…‘Starkrimson’ and identified two WRKY transcription factors, WRKY26 and WRKY31 , which act together on the MYB promoter, thereby affecting anthocyanin biosynthesis and transport. Plants are mainly regulated by structural genes in the flavonoid biosynthesis pathway, and regulatory genes such as transcription factors mainly affect the synthesis of flavonoid substances by influencing structural genes, but the role of regulatory genes should not be underestimated ( Liu et al., 2021b ; Ye et al., 2019 ). Xi et al.…”

Molecular Mechanism of Exogenous ABA to Enhance UV-B Resistance in Rhododendron chrysanthum Pall. by Modulating Flavonoid Accumulation

“…While transcription factors have no impact on DFs, they have the capability to either directly or indirectly stimulate the promoters of genes linked to flavonoid biosynthesis, thus controlling the ultimate accumulation of flavonoids [62,63]. In order to make progress in revealing the regulatory mechanisms of transcription factors to UV-B stress in R. chrysanthum, TFs that showed differential changes after UV-B stress were correlated with differential enzymes in the flavonoid synthesis pathway (Figure 7D).…”

Two genes, ANS and UFGT2, from Vaccinium spp. are key steps for modulating anthocyanin production

“…It is the overall activity of the R2R3-MYB TFs that is thought to be the main determinant for the amount of anthocyanin produced ( Schwinn et al., 2006 ; Allan et al., 2008 ). Furthermore, meta-analysis shows that overexpression of MYB TFs significantly impact the regulation of a set of structural genes together with increased anthocyanin production ( Liu et al., 2021b ). However, the manipulation of wide-acting MYB TFs can potentially lead to collateral consequences.…”