Fig. 1

Mulberry type III polyketide synthase superfamily. a Phylogenetic relationships among the type III PKS genes. Branch length is defined as the number of nucleotide substitutions per codon according to PAML. Different colors indicate higher posteriori probabilities of evolving under different selection regimens: red and blue correspond to positive and purifying selections, respectively, while black indicates the selection constraints of the branch are relaxed relative to the other branches of the same clade. The lowercase letters refer to the following: a, branch ancestral to the MnCHS and MnSTS families; b, branch ancestral to the MnSTS family clade; c, branch ancestral to the MnCHS family clade. *: genes without expression data (b) Intron/exon structure of the type III PKS genes. Boxes: exon; black line: intron; cyan boxes: N-terminal chalcone/stilbene synthase domain (IPR001099); yellow boxes: C-terminal chalcone/stilbene synthase domain (IPR012328)