Fig. 7

PabHLH1 transcription and biochemical analysis in transgenic P. appendiculatum thallus. a The transcription of PabHLH1 in P. appendiculatum wild-type (WT) and the transgenic overexpression PabHLH1 gene thallus (OE). b The contents of flavonoids in WT and OE thallus. c Representative HPLC profiles of methanolic bibenzyls extracted from OE thallus (solid line) and WT thallus (red dashed line). The major bibenzyls identified were: LA = lunularic acid, RC = riccardin C, RD = riccardin D. The internal standard was baicalein. d The bibenzyls contents quantified according to the HPLC analysis of WT and OE P. appendiculatum thallus using corresponding sdandard curve of LA, RC and RD. e The transcript abundance of genes encoding enzymes involved in bibenzyl and flavonoid synthesis in WT and OE thallus. Data represent mean ± S.D. with three biological repeats. *p < 0.05, ** p < 0.01 according to Student’s t-test