Identification of key gene networks controlling anthocyanin biosynthesis in peach flower.

• The variation in flower color is due to the accumulation of different kinds of flavonoids. • A co-expressed network of genes containing the structural and regulatory genes of anthocyanin biosynthetic pathway were constructed. • PpMYB108 was found to be associated with anthocyanin biosynthesis and red color of peach flower. • PpMYB108 binds with the promoter of PpDFR through a 6bp MYB binding site. Flavonoids, particularly anthocyanin is the main pigment that determined the red color of peach flowers, and help the plant to attract pollinators, protect the reproductive organs of flower from photo-oxidative effects of light and various non-communicable diseases. Through weightage gene coexpression network analysis (WGCNA) we identified a network of 15 hub genes that co-expressed throughout peach flower development including 5 genes coded for the key enzymes (CHI, F 3′ H, DFR, LAR and UFGT) of flavonoid biosynthetic pathway and 1 gene Prupe.1G111700 identified as R2R3 family transcription factor MYB108. Over expression of PpMYB108 significantly increased anthocyanin biosynthesis in Tobacco flowers. Moreover, the expression correlation between PpMYB108 and PpDFR, suggests that PpMYB108 play the role of transcriptional activator for PpDFR. This was further supported by a 6 bp insertion of MYB biding site in the core promoter region of PpDFR in red flower. The positive interaction of PpMYB108 with PpDFR promoter from red flower was confirmed in yeast one hybrid assay. These findings may be helpful in peach breeding programs as well as in identifying anthocyanin related genes in other species. [ABSTRACT FROM AUTHOR]