*2.5. The Relationship between Structure Genes and TFs*

Through the analysis of the expression patterns of ABP-related genes and the phylogenetic tree of R2R3-MYB, we obtained several candidate genes that correlate with floral color intensity. We constructed a co-expression network (Figure 8) to identify the interactions between ABP-related genes and MBW complex proteins (MYB, bHLH, and WDR). The results show that ten structure unigenes and five MBW complex transcriptional unigenes composed of two R2R3-MYB, two bHLH and one WD40 unigene exhibited interaction relationships. The expression pattern of *PlMYB10* coincided with those of PlbHLH20 (Unigene0062784) and PlbHLH26 (Unigene00660), while *PlbHLH20* and *PlbHLH26* also correlated with *PlWD40-1* (Unigene0002153). PlMYB10 also showed a linear relationship with *PlFLS*. We therefore inferred that *PlMYB10* may interact with *PlbHLH20* or *PlbHLH26*, and *PlWD40-1* to form a MBW transcriptional complex, and regulate the expression pattern of *PlFLS*, finally affecting flower polymorphism in *P. limprichtii.*

**Figure 8.** A co-expression network of anthocyanin biosynthesis pathway-related genes and transcription factors involved in pigmentation. Rose-purple circle represents structural genes; dark-gray circle represents R2R3-MYB; light-gray circle represents bHLH; pink circle represents WD40.
