Fig. 7: Analysis of anthocyanins and PA precursors in seeds of BZ1 and bz1 mutant maize.

a Selected ion chromatograms of catechin and epicatechin (left, m/z = 289.0718 ± 10 ppm), 4β-(S-cysteinyl)-catechin and 4β-(S-cysteinyl)-epicatechin (middle, m/z = 408.0759 ± 10 ppm), as well as cyanidin 3-O-glucoside (right, m/z = 447.0940 ± 10 ppm) in seeds of BZ1 and bz1 maize. b Anthocyanin contents in BZ1 and bz1 seeds. Data are presented as mean ± S.D. (n = 3, independent biological replicates). Asterisks indicate significant difference between BZ1 and bz1 samples at P < 0.01 as determined by two-tailed Student’s t-test. c Chiral-HPLC analysis of the stereochemistry of epicatechin monomers in bz1 seeds. Red arrow indicates the (+)-epicatechin in PAs extracted from bz1 seeds. d Selected ion chromatograms of procyanidin dimers (m/z = 577.1360 ± 10 ppm) in BZ1 and bz1 maize seeds. SD, chemical standard; (-)-epi and (+)-epi, (-)-epicatechin and (+)-epicatechin; c-cys and epi-cys, 4β-(S-cysteinyl)-catechin and 4β-(S-cysteinyl)-epicatechin; C3G, cyanidin 3-O-glucoside; B3, procyanidin B3 dimer; iso-B2, procyanidin B2 isomer with (+)-epicatechin as the starter unit; iso-B4, procyanidin B4 isomer with (+)-epicatechin as the starter unit. Source data for Fig. 7b are provided in the Source Data file.