Induction by light of hydroxycinnamoyl-CoA: Quinate hydroxycinnamoyl transferase in buckwheat (Fagopyrum esculentum Moench): Absence of feed-forward control by trans-cinnamate.

The light-induced increase in the activity of hydroxycinnamoyl-CoA: quinate hydroxycinnamoyl transferase (CQT) in hypocotyls of etiolated buckwheat seedlings is not suppressed by aminooxy acetic acid, an inhibitor of cinnamic acid formation in this tissue. Incubation of hypocotyls in 2 mmol l(-1) trans-cinnamate in the dark does not increase CQT activity. Thus, trans-cinnamate does not appear to mediate the effect of light on CQT in buckwheat hypocotyls.