Characterization in vitro and in vivo of the putative multigene 4-coumarate:CoA ligase network in Arabidopsis: syringyl lignin and sinapate/sinapyl alcohol derivative formation

Detailed characterization of all bona fide At4CL genes, and their corresponding recombinant proteins, together with that of an At4CL5 gene knockout, revealed that formation of syringyl lignin and sinapate ester does not occur via direct ligation of sinapic acid.