The heterologous expression of PabHLH1 in A. thaliana
(a) RT-PCR analysis of expression levels of PabHLH1 in the WT and PabHLH1-OE transgenic Arabidopsis seedlings. WT, wild-type A. thaliana; OE: transgenic A. thaliana lines carrying PabHLH1. b Representative HPLC profiles of methanolic extracts of transgenic Arabidopsis seedlings line (blue solid line) and WT seedlings (red dashed line). The major flavonoid or sinapic acid derivatives are: K1, Kaempferol 3-O-[6″-O-(rhamnosyl) glucoside] 7-O-rhamnoside; K2, kaempferol 3-O-glucoside 7-O-rhamnoside; K3, kaempferol 3-O-rhamnoside 7-O-rhamnoside; K4, kaempferol 3-O-rhamnoside 7-O-glucoside; SM, sinapoyl malate; SG, sinapoyl glucose. The internal standard chrysin are labeled. c The contents of kaempferol derivatives in methanolic extracts of Arabidopsis seedlings by HPLC analysis. d The contents of anthocyanin in methanolic extracts of Arabidopsis seedlings. e Seedlings of 5 days after germination of wild type and transgenic lines OE1, OE2 and OE3, showing the more anthocyanin accumulation in the hypocotyl in transgenic lines indicated with arrow. f qRT-PCR analysis of the genes encoding key enzymes in lines OE1, OE2 and OE3. Data represent mean ± S.D. with three biological repeats. *p < 0.05, ** p < 0.01 according to Student’s t-test.