Fig. 4

The anthocyanin biosynthetic pathway and expression levels of structural and positive regulatory genes in B. oleracea. The pathway can be divided into two sections: the phenylpropanoid and the flavonoid pathways. Two types of genes are involved in the flavonoid pathway: early biosynthetic genes (EBGS) and late biosynthetic genes (LBGs). Red type indicates biosynthetic enzymes. The ellipses “M”, “B”, and “W” represent the MYB, bHLH, and WD40 proteins involved in the positive regulation of anthocyanin synthesis. The expression levels of coding genes is indicated by blue and red shading, which represents low to high expression levels, respectively. The color scale corresponds with the mean-centered log2-transformed FPKM values, which are identical to those in Fig. 4