R2R3-MYB Transcription Factors Regulate Anthocyanin Biosynthesis in Grapevine Vegetative Tissues

Abstract

Anthocyanins with important physiological functions mainly accumulate in grape berry, but teinturier grape cultivars can accumulate anthocyanins in both reproductive and vegetative tissues. The molecular regulatory mechanisms of anthocyanin biosynthesis in grapevine reproductive and vegetative tissues are different. Therefore, teinturier grapevine cultivar provides opportunities to investigate transcriptional regulation of vegetative anthocyanins, and to compare with mechanisms that regulate grape berry anthocyanins. Yan73 is a teinturier Vitis vinifera variety with vegetative tissues able to accumulate anthocyanins, but the anthocyanin pattern and the molecular mechanism regulating anthocyanin biosynthesis in these tissues remain uncharacterized. We analyzed the anthocyanin metabolic and transcriptome profiles of the vegetative tissues of Yan73 and its male parent with HPLC-ESI-MS/MS and RNA-sequencing technologies. Yan73 vegetative tissues had relatively high 3 -OH, acylated, and methoxylated anthocyanins. Furthermore, peonidin-3-O-(trans-6-coumaryl)-glucoside is the most abundant anthocyanin in Yan73 grapevine vegetative tissues. A total of 30,17 and 10 anthocyanin biosynthesis genes showed up-regulated expression in Yan73 leaf, stem and tendril, respectively, indicating anthocyanin biosynthesis in Yan73 vegetative tissues is regulated by transcription factors. The up-regulated expression of VvMYBA1 on chromosome 2 and VvMYBA5, VvMYBA6, and VvMYBA7 on chromosome 14 are responsible for the anthocyanin patterns of Yan73 vegetative tissues. The expression of a set of R2R3-MYB C2 repressor genes is activated and may negatively regulate anthocyanin biosynthesis in Yan73 vegetative tissues. These findings enhance our understanding of anthocyanin biosynthesis in grapevine.

VvMYB15 and VvWRKY40 Positively Co-regulated Anthocyanin Biosynthesis in Grape Berries in Response to Root Restriction

“…MYBA1 and MYBA2 at the color locus are the major genetic determinants of grape skin color, and the mutation of two functional genes (VvMYBA1, VvMYBA2) from these loci lead to white skin color ( Jiu et al, 2021 ), while VvMYB86 can inhibit anthocyanin biosynthesis primarily in grape berry by downregulating the expression of two structural genes including VvANS and VvUFGT ( Cheng et al, 2021 ). Transcriptome and metabolic data revealed that up-regulated expression of VvMYBA1, VvMYBA5, VvMYBA6 and VvMYBA7 are responsible for the specific anthocyanin patterns of Yan73 vegetative tissues, with VvMYB5A and VvMYB6A likely encoding the major regulators of anthocyanin biosynthesis in Yan73 vegetative tissues, simultaneously, VvMYBC2-L1 and VvMYBC2-L3, as repressor genes, are activated and may negatively regulated anthocyanin biosynthesis in vegetative tissues, therefore maintaining the balance of anthocyanin level ( Xie et al, 2020 ). VvMYBPA1 did not activate the promoter of VvUFGT , which encodes the anthocyanin specific flavonoid-3- O -glucosyltransferase, while activated the expression of VvLAR and VvANR and further regulate the proanthocyanidin synthesis, indicating that tissue and temporal-specific expression of VvANR and VvLAR correlates with proanthocyanidins (PAs) accumulation prior to veraison in grapes ( Bogs et al, 2007 ).…”

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).…”

“…Numerous previous studies have reported on anthocyanin biosynthesis-associated genes and their role in the regulation of color phenotypes and tolerance to HL stress [ 79 , 80 , 81 ]. The functions of these genes have also been studied in detail using overexpression and/or silencing strategies in Arabidopsis or other plant species, such as apple [ 82 ], grape [ 42 ] and wheat [ 50 ]. Documenting the transcriptional expression of key anthocyanin biosynthesis-related genes may provide further insight into plant response to HL stress.…”

“…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 ]. For example, PRODUCTION OF ANTHOCYANIN PIGMENTATION 1 ( PAP1 )/ MYB75 , PAP2 / MYB90 , MYB113, and MYB114 ( R2R3-MYB family members) have been identified and well-studied in Arabidopsis [ 41 ].…”

Light Induced Regulation Pathway of Anthocyanin Biosynthesis in Plants

“…Among these transcription factors, MYB transcription factors play a significant role in regulating anthocyanin biosynthesis. Many anthocyanin-related R2R3-MYB factors have been identified from many plants such as Arabidopsis [39], grape [53], Gerbera [54], eggplant [55], tomato [55], populous [56], apple [57,58], etc. Most of these are R2R3-MYB proteins with the motif [D/E]LX2[R/K]X3LX6LX3R in the R3 domain, which is necessary to interact with bHLH acting as activators to increase anthocyanin accumulation [59].…”