Expression profile of anthocyanins relative genes in the mutant and the wild line
A total of 1729 DEGs (Differentially Expressed Genes) were detected between the green buds of GS and the purple buds of PS. The broccoli reference genome contained 53 genes in the 229.6 Kb range between 59999594 and 60229243bp of the C9 chromosome. Out of the 53 genes, only one gene, BolC9t59639H (F3’H) , was differentially expressed between the mutant and the wild line. The expression ofBolC9t59639H (F3’H) in the buds of the mutant GS was one-third of the wild line PS at low temperature. Except for the BolC9t59639H (F3’H) , no other genes were differentially expressed between the mutant and the wild line within the target range on chromosome 9. According to KEGG database, 43 genes relative with anthocyanin biosynthesis and regulation pathway were found to express in the buds of broccoli PS and GS at low temperature. Besides BolC9t59639H (F3’H) , the expression level of BolC3t18539H (FLS ) was different in both buds, which had almost 1.5 times in the buds of the mutant GS. The KEGG Pathway enrichment analysis showed that BolC9t59639H (F3’H, EC: 1.14.14.82) participated in the biosynthesis of cyanidins and delphinidins, while BolC3t18539H (FLS, EC: 1.14.20.6) took part in the biosynthesis of flavone and flavonol biosynthesis (Figure 4A).