MYB Genes Involved in Domestication and Crop Improvement

Abstract

Domestication of the world's crop species has been achieved through improvements in yield, and product qualities, with or without the guidance of scientific knowledge. These selection pressures are applied by breeders (and before them, farmers) both intentionally and unintentionally to improve crop features, which have often been grouped into ‘production traits’ and ‘quality traits’. New approaches to breeding that incorporate genome sequencing, mapping, and identification of genes underlying traits have revealed new variants in the family of transcription factors (TFs) called MYBs as driving important features in both these categories of domestication traits. In this article, we review the progress in understanding the role of MYB TFs in crop performance, as well as reasons to predict further gains in yield and quality centred on the MYB TF family.

The Coordinated Action of MYB Activators and Repressors Controls Proanthocyanidin and Anthocyanin Biosynthesis in Vaccinium

“…The flavonoid pathway is regulated at the transcriptional level, with an MBW complex promoting transcription of biosynthetic genes, consisting of R2R3 MYB, bHLH and WDR proteins (Baudry et al, 2004;Albert and Allan, 2021). The MYB transcription factor (TF) determines the specificity of the complex for the different biosynthetic gene promoters.…”

“…SG6 MYBs are involved in anthocyanin regulation, upregulating flavonoid biosynthetic genes and the anthocyanin specific UFGT. These are key regulators for controlling anthocyanin production in fruit (Albert and Allan, 2021), including blueberry and bilberry (Plunkett et al, 2018;Karppinen et al, 2021). An additional class of MYBs, MYBPA1-type, are dual regulators of PA and anthocyanin biosynthesis in fruit and are required for full activation of both pathways (Karppinen et al, 2021;Lafferty et al, 2022).…”

The first chromosome-level Fallopia multiflora genome assembly provides insights into stilbene biosynthesis

“…In A. thaliana , R2R3 MYB is divided into 25 subgroups (SG) according to phylogeny [ 44 ]. SG1–SG7 MYBs are involved in the synthesis of specialized metabolites with SG1 participating in cuticular wax synthesis of cuticular wax and stomatal control, while SG2s involved in phytoalexin (stilbene) synthesis, SG3s in lignification, and SG4s, SG5s, SG6s, and SG7s in phenylpropanoid, proanthocyanidin, anthocyanin, and flavonol biosynthesis, respectively [ 45 ]. To identify the subgroups of F. multiflora MYBs, a phylogenetic tree of the A. thaliana and V. vinifera MYB sequences was constructed.…”

Vaccinium as a comparative system for understanding of complex flavonoid accumulation profiles and regulation in fruit

“…The R2R3-MYB genes can be phylogenetically clustered into subgroups (SG), which generally have conserved functions among flowering plants; e.g. those belonging to SG5 regulate PAs, SG6 regulates anthocyanins, and SG7 regulates flavonols or flavones ( Stracke et al 2001 ; Albert and Allan 2021 ). These insights have largely come from genetic models such as maize, petunia, Antirrhinum, and Arabidopsis (reviewed in Albert et al 2022 ), but it is becoming clear flavonoid regulation is more nuanced, particularly in crops with complex flavonoid profiles that change throughout different developmental stages ( Fig.…”

“…This is because variants of SG6 MYB genes can give rise to fruit with different colors or patterns, which have been selected for or against. Thus, SG6 MYB alleles have been identified in numerous crops that are responsible for determining anthocyanin content or patterning ( Paauw et al 2019 ; reviewed in Albert and Allan 2021 ).…”