Fig. 5

Expression levels of structural genes and metabolites involved in the flavonoid biosynthesis pathway in maize kernels. The heatmap represents the expression of corresponding genes, and white to red in the heatmap indicates the expression levels of structural genes ranging from low to high. The color of the heatmap from yellow to blue indicates the accumulation levels of metabolites ranging from low to high. Enzymes in this pathway are shown as follows: PAL, phenylalanine ammonia lyase; 4CL, 4-coumarate-CoA ligase; CHS, chalcone synthase; CHI, chalcone isomerase; CYP73A, trans-cinnamate 4-monooxygenase, F3H, flavanone 3-hydroxylase; DFR, dihydroflavonol 4-reductase; ANS, anthocyanidin synthase; FLS, flavonol synthase, CYP75A, flavonoid 3’,5’-hydroxylase, and CYP75B1, flavonoid 3’-monooxygenase