GWA Mapping of Anthocyanin Accumulation Reveals Balancing Selection of MYB90 in Arabidopsis thaliana

Abstract

Induction of anthocyanin accumulation by osmotic stress was assessed in 360 accessions of Arabidopsis thaliana. A wide range of natural variation, with phenotypes ranging from green to completely red/purple rosettes, was observed. A genome wide association (GWA) mapping approach revealed that sequence diversity in a small 15 kb region on chromosome 1 explained 40% of the variation observed. Sequence and expression analyses of alleles of the candidate gene MYB90 identified a causal polymorphism at amino acid (AA) position 210 of this transcription factor of the anthocyanin biosynthesis pathway. This amino acid discriminates the two most frequent alleles of MYB90. Both alleles are present in a substantial part of the population, suggesting balancing selection between these two alleles. Analysis of the geographical origin of the studied accessions suggests that the macro climate is not the driving force behind positive or negative selection for anthocyanin accumulation. An important role for local climatic conditions is, therefore, suggested. This study emphasizes that GWA mapping is a powerful approach to identify alleles that are under balancing selection pressure in nature.

Discovering variation of secondary metabolite diversity and its relationship with disease resistance in Cornus florida L.

“…This model has been used in genomewide association (GWA) studies of Arabidopsis thaliana (Bac‐Molenaar, Fradin, Rienstra, Vreugdenhil, & Keurentjes, 2015; Fournier‐Level et al., 2011; Li, Huang, Bergelson, Nordborg, & Borevitz, 2010; Li et al., 2014; Strauch et al., 2015) because of its computational efficiency, and its ability to handle and control for population stratification (Price, Zaitlen, Reich, & Patterson, 2010) and environment. We tested for both SNP associations to each metabolite and for SNP associations to the property of chemical richness.…”

Identification of the Eutrema Salsugineum EsMYB90 gene important for anthocyanin biosynthesis

“…Chrysanthemum [10], grape hyacinth (Muscari armeniacum) [36], grapevine (Vitis vinifera) [37,38], chinese bayberry(Myrica rubra) [6,39], Epimedium sagittatum [40,41], poplar (Populus spp) [42] and potato (Solanum tuberosum L) [43]. In addition, some MYB genes are up-regulated under various stress conditions [15,17]. However, the transcriptional regulation of anthocyanin synthesis by MYB in stress-tolerant plants is not well studied.…”

“…In higher plants, PAs and anthocyanin biosynthesis are regulated by different sets of MYB-bHLH-WD40 (MBW) complexes, and the R2R3-MYBs play vital roles in transcriptional regulation of anthocyanins biosynthesis[12,19,20,23,25,34,35]. Our results shed light on the molecular mechanism by which a novel R2R3-MYB controls PA and anthocyanin biosynthesis via promoting expression of PA and anthocyanin biosynthesis genes.In Arabidopsis, MYB75, MYB90, MYB113, and MYB114 function redundantly by participating in the MBW (MYB-bHLH-WD40) complex to regulate PA and anthocyanin biosynthesis.Overexpression of one of these four MYBs is sufficient to increase anthocyanin accumulation in young leaves[15,17].EsMYB90 is a R2R3-MYB, containing a conserved [D/E]Lx2[R/K]x3Lx6Lx3R motif (black arrows) required for interaction with R/B-like bHLH proteins, which was not found in EsMyb15 (XP_006406061), EsMyb106(XP_006390428), EsMyb108 (XP_006407939), EsMyb -related protein 340 (XP_006395259 ) from E. salsugineum.The ANDV (red box A) and KPRPR [S/T]F motifs (blue box B) characterizing anthocyanin-promoting MYBs exist in EsMYB90 protein but not in other five EsMYBs [Myb5 (XP_006407201), Myb15, Myb106, Myb108, Myb-related Protein 340] (Additional file 1: Fig.…”

Identification of the Eutrema Salsugineum EsMYB90 gene important for anthocyanin biosynthesis

“…Chrysanthemum [10], grape hyacinth (Muscari armeniacum) [36], grapevine (Vitis vinifera) [37,38], chinese bayberry(Myrica rubra) [6,39], Epimedium sagittatum [40,41], poplar (Populus spp) [42] and potato (Solanum tuberosum L) [43]. In addition, some MYB genes are up-regulated under various stress conditions [15,17]. However, the transcriptional regulation of anthocyanin synthesis by MYB in stress-tolerant plants is not well studied.…”