The interconnections in the pathways of central metabolism and aromatic amino acids for (A) WT and (B) tt4 plants. The metabolites whose levels changed less than 10% (p < 0.05) in tt4/WT are indicated with blue characters in (B); the metabolites with black characters in (B) had no significant changes; and the metabolites with gray characters were undetectable. The gray arrows indicate the metabolic pathways. The curved lines show correlations between metabolite pairs. The thickness of the edges between the metabolites represents the significance of correlations (r
> 0.88). Although the sinapoylmalate level in tt4 did not increase, the correlations of malate with aromatic compounds were intensified in the tt4 mutant, indicating possible adaptive response to UV stress under the flavonoid-deficient tt4 mutant by reconfiguration of the networks in tt4. Metabolites with the asterisk (*) were quantified by using LC-Q-TOF/MS analysis (see Additional File 3). Abbreviations: CHS, chalcone synthase; p-Coumarate, 4-Hydroxycinnamic acid.