Suppression of a BAHD acyltransferase decreases <i>p</i>‐coumaroyl on arabinoxylan and improves biomass digestibility in the model grass <i>Setaria viridis</i>
Thatiane Rodrigues Mota, Wagner Rodrigo de Souza, Dyoni Matias de Oliveira, Polyana Kelly Martins, Bruno Leite Sampaio, Felipe Vinecky, Ana Paula Ribeiro, Karoline Estefani Duarte, Thályta Fraga Pacheco, Norberto de Kássio Vieira Monteiro, Raquel Bombarda Campanha, Rogério Marchiosi, Davi S. Vieira, Adilson Kenji Kobayashi, Patrícia Abrão de Oliveira Molinari, Osvaldo Ferrarese‐Filho, R. A. C. Mitchell, Hugo Bruno Correa Molinari, Wanderley Dantas dos Santos
Abstract
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.