Immunolocalization of the β– <i>O</i> –4 linked structure of lignin in wood and bamboo cell walls using a novel monoclonal antibody

Abstract A mouse monoclonal antibody was generated against a β– O –4 oligomer- p -aminohippuric acid-( p AHA)-bovine serum albumin (BSA) conjugate. Competitive ELISA showed that the antibody reacted specifically with β– O –4 oligomer conjugate and did not react with other dimeric model compound conjugates containing the β–5, β–β, or 5–5 linkages. This antibody reacted with both the β– O –4 linked guaiacyl and syringyl structures. In Chamaecyparis obtusa , labeling was strong in the secondary walls (SW), and weak in the compound middle lamella (CML). In Betula grossa , labeling was strong in the outer SW of wood fibers and uniform in the SW of vessel elements and the inner part of the SW of wood fibers. In contrast, labeling was strong in wood fibers rich in syringyl lignin in Quercus crispula and weak in CML, including cell corners, the SW of vessel elements, and vasicentric tracheids rich in guaiacyl lignin. In Phyllostachys edulis , labeling was uniform in developing fiber SW and stronger in inner part in developed fiber SW. The localization patterns were like those of feruloyl arabinoxylan epitopes. This novel antibody will be an effective tool to immunolocalize the β– O –4 linked structure of lignin in plant cell walls.