MYB-Mediated Regulation of Anthocyanin Biosynthesis

Abstract

Anthocyanins are natural water-soluble pigments that are important in plants because they endow a variety of colors to vegetative tissues and reproductive plant organs, mainly ranging from red to purple and blue. The colors regulated by anthocyanins give plants different visual effects through different biosynthetic pathways that provide pigmentation for flowers, fruits and seeds to attract pollinators and seed dispersers. The biosynthesis of anthocyanins is genetically determined by structural and regulatory genes. MYB (v-myb avian myeloblastosis viral oncogene homolog) proteins are important transcriptional regulators that play important roles in the regulation of plant secondary metabolism. MYB transcription factors (TFs) occupy a dominant position in the regulatory network of anthocyanin biosynthesis. The TF conserved binding motifs can be combined with other TFs to regulate the enrichment and sedimentation of anthocyanins. In this study, the regulation of anthocyanin biosynthetic mechanisms of MYB-TFs are discussed. The role of the environment in the control of the anthocyanin biosynthesis network is summarized, the complex formation of anthocyanins and the mechanism of environment-induced anthocyanin synthesis are analyzed. Some prospects for MYB-TF to modulate the comprehensive regulation of anthocyanins are put forward, to provide a more relevant basis for further research in this field, and to guide the directed genetic modification of anthocyanins for the improvement of crops for food quality, nutrition and human health.

Multiple Functions of MYB Transcription Factors in Abiotic Stress Responses

“…Among these functions, MYB proteins have been particularly well studied as regulators of phenylpropanoid metabolism, such as the biosynthesis of proanthocyanidins (PAs), anthocyanins, flavonols, and lignin in plants. For example, MYB proteins can bind to the bHLH transcription factor and WD40 protein to form the MBW complex and activate the biosynthesis of PAs and anthocyanins [ 3 , 4 , 5 , 6 ]. Multiple studies have indicated the critical roles of MYB transcription factors in plant stress responses, especially in abiotic stresses [ 7 , 8 , 9 ].…”

Transcriptome Analysis Reveals Roles of Anthocyanin- and Jasmonic Acid-Biosynthetic Pathways in Rapeseed in Response to High Light Stress

“…Notably, all of 15 transcripts associated with JA biosynthesis identified by MapMan analysis were found to respond to HL stress and were up-regulated by HL ( Figure 8 A). Several studies have reported that JA mediates the biosynthesis and accumulation of anthocyanins in plants when they are exposed to adverse environmental conditions [ 40 , 42 , 44 , 45 ]. In our study, RT-qPCR analysis of five JA biosynthesis-associated genes also indicated that the expression of all of them was induced in rapeseed leaves by HL stress, supporting the results of the transcriptome analysis ( Figure 8 B).…”

“…R2R3-MYB TFs, a type of the ternary MBW complex, have been reported to play a dominant role in the regulation of anthocyanin biosynthesis [ 40 ]. Notably, MYB75/PAP1 and MYB90/PAP2 genes are induced by light in Arabidopsis [ 84 ], and their orthologs were found to be induced by 7- and 23.5-fold, respectively, in leaves of rapeseed seedlings exposed to HL conditions for 16 h in rapeseed under HL ( Figure 9 C) which is consistent with the observed anthocyanin accumulation under HL conditions in our study ( Figure 1 C,D).…”

“…It has been well documented that anthocyanin biosynthesis is primarily regulated by three types of transcription factors (TFs), namely MYB , bHLH (basic helix-loop-helix), and WD40 that form a MBW complex, in which MYB TFs play a crucial role [ 25 , 39 , 40 ]. R2R3-type MYB s are predominantly responsible for activation of anthocyanin biosynthesis, and many R2R3-MYB s have been well characterized in various plant species, including Arabidopsis thaliana [ 41 ], grape ( Vitis vinifera ) [ 42 ], Medicago truncatula [ 43 ], strawberry ( Fragaria × ananassa ) [ 44 ], and apple ( Malus × domestica ) [ 45 ].…”

The Expression of IbMYB1 Is Essential to Maintain the Purple Color of Leaf and Storage Root in Sweet Potato [Ipomoea batatas (L.) Lam]

“…R2R3-MYBs such as IbMYB1 can independently initiate the transcription of anthocyanin biosynthesis genes ( Stracke et al, 2007 ; Dubos et al, 2008 ; Dong, 2014 ; Dong et al, 2014 ) or can interact with other TFs to form the MBW complex to activate anthocyanin biosynthesis in sweet potato and other plants ( Dubos et al, 2008 ; Davies et al, 2012 ; Zhu et al, 2015 ; Deng et al, 2020 ; Yan et al, 2021 ). It has been confirmed that IbMYB1-2 plays a vital regulatory role in anthocyanin accumulation in storage roots ( Tanaka et al, 2011 ), but it is not necessary in all varieties for the expression of IbMYB1 ( Kim et al, 2010 ; Li et al, 2019 ; Zhang et al, 2020 ).…”