Figure 1.

Flavonoid biosynthesis is differentially regulated in starch-deficient adg1-1 and the triose phosphate/phosphate translocator mutant (tpt-2).

(A) Schematic presentation of the biochemical pathway that leads to the formation of flavonoids. Further information is provided in the main text.

(B) Phenotypes of the wild type (WT; Col-0) and adg1-1 and tpt-2 mutants before (t0) and after exposure to continuous high light (HL) for 24 h.

(C) Anthocyanin accumulation (expressed as cyanidin equivalents) in WT (Col-0), adg1-1, and tpt-2 after exposure to continuous HL for 24 h. Plants were shifted to HL 2 h after the onset of light. Statistical significance of differences between the wild type and mutants was calculated using 1-way ANOVA (Dunnett’s multiple comparisons test) relative to Col-0. Values are means ± standard deviations (n = 6), and the p values are shown.

(D and E) Relative expression of PAP1(D) and LDOX(E) in WT, adg1-1, and tpt-2 after HL treatment. Changes in gene expression were calculated using the 2^−ΔΔCt method with SAND as the reference gene and are expressed relative to Col-0 before the HL shift. Statistical significance of differences between Col-0 and mutants was analyzed using Student’s t test. Values are means ± standard deviations (n = 3), and the p values are shown. For all experiments, seedlings from at least 3 different pots shifted at the same time were harvested, and each sample consisted of approximately 10–15 seedlings.