Search

Summary: Grass cell walls have hydroxycinnamic acids attached to arabinosyl residues of arabinoxylan (AX), and certain BAHD acyltransferases are involved in their addition. In this study, we characterized one of these BAHD genes in the cell wall of the model grass Setaria viridis. RNAi silenced lines of S. viridis (SvBAHD05) presented a decrease of up to 42% of ester‐linked p‐coumarate (pCA) and 50% of pCA‐arabinofuranosyl, across three generations. Biomass from SvBAHD05 silenced plants exhibited up to 32% increase in biomass saccharification after acid pre‐treatment, with no change in total lignin. Molecular dynamics simulations suggested that SvBAHD05 is a p‐coumaroyl coenzyme A transferase (PAT) mainly involved in the addition of pCA to the arabinofuranosyl residues of AX in Setaria. Thus, our results provide evidence of p‐coumaroylation of AX promoted by SvBAHD05 acyltransferase in the cell wall of the model grass S. viridis. Furthermore, SvBAHD05 is a promising biotechnological target to engineer crops for improved biomass digestibility for biofuels, biorefineries and animal feeding. Significance Statement: A BAHD acyltransferase gene was studied, and it was demonstrated that its suppression causes reduction of ester‐linked p‐coumaric acid in the cell walls of Setaria viridis. RNAi silenced lines had higher biomass digestibility with no alteration in the biomass production. Molecular dynamics simulation reinforced the evidence that SvBAHD05 is mainly responsible for the incorporation of p‐coumaric acid onto arabinoxylan, the main hemicellulose in grass cell walls. [ABSTRACT FROM AUTHOR]