Transcriptome Analysis Reveals Candidate Genes Involved in Anthocyanin Biosynthesis in Flowers of the Pagoda Tree (Sophora japonica L.)

The flowers of pagoda tree (Sophora japonica L.) are white, which limited its ornamental value and caused few researches on flower color anthocyanin accumulation. A pink mutant (PM) was discovered, provided an opportunity to investigate biosynthesis in flowers. In this study, the flavone/flavonol contents petals PM wild type (WT; white flower) were measured. content total anthocyanins significantly higher than WT at four floral stages (S1–S4). There no significant differences flavonol between these two varieties each stage, indicating that did not influence color, while a key factor determine coloration. Then, transcriptome analysis performed by using S1–S4. Differentially expressed genes encoding chalcone synthase, flavanone 3-hydroxylase, 3?-hydroxylase, dihydroflavonol-4-reductase, anthocyanidin UDP-glucose: flavonoid-3-O-glucosyltransferase identified. Importantly, we found SjDFR2 might be gene accumulation petals. Transcription factors, SjPAP1, SjMYB111, SjMYB1b, SjMYBL2, SjTT8, WD40 protein SjTTG1, play critical roles regulation Moreover, regulatory factors involved phytohormone signal pathway (SjIAA19, SjIAA27, SjAXR3, SjARF20, SjERS1), light (SjHY5), also screened out. These results will provide some new insights into control tree, as well candidate breed novel colors molecular methods.