4CL activity was measured as described in Yun et al. (2006) with some modifications. The reaction mixtures contained 0.3 mL of enzyme extracts, 1.35 mL of 15 M magnesium sulfate, 0.45 mL of 50 M ATP, 0.45 mL of 1 M CoA and 0.45 mL of 5 M p-coumaric acid. The absorbance was measured at 333 nm. 4CL activity was expressed as U kg−1 protein, where U = 0.01 A333 s−1.