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Research article - Peer-reviewed, 2020

Hunting monolignol transporters: membrane proteomics and biochemical transport assays with membrane vesicles of Norway spruce

Vaisanen, Enni; Takahashi, Junko; Obudulu, Ogonna; Bygdell, Joakim; Karhunen, Pirkko; Blokhina, Olga; Laitinen, Teresa; Teeri, Teemu H.; Wingsle, Gunnar; Fagerstedt, Kurt, V; Karkonen, Anna

Abstract

Both the mechanisms of monolignol transport and the transported form of monolignols in developing xylem of trees are unknown. We tested the hypothesis of an active, plasma membrane-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared from developing xylem and lignin-forming tissuecultured cells of Norway spruce (Picea abies L. Karst.), as well as from control materials, comprising non-lignifying Norway spruce phloem and tobacco (Nicotiana tabacum L.) BY-2 cells. Xylem and BY-2 vesicles transported both coniferin and p-coumaryl alcohol glucoside, but inhibitor assays suggested that this transport was through the tonoplast. Membrane vesicles prepared from lignin-forming spruce cells showed coniferin transport, but the K-m value for coniferin was much higher than those of xylem and BY-2 cells. Liquid chromatography-mass spectrometry analysis of membrane proteins isolated from spruce developing xylem, phloem, and lignin-forming cultured cells revealed multiple transporters. These were compared with a transporter gene set obtained by a correlation analysis with a selected set of spruce monolignol biosynthesis genes. Biochemical membrane vesicle assays showed no support for ABC-transporter-mediated monolignol transport but point to a role for secondary active transporters (such as MFS or MATE transporters). In contrast, proteomic and co-expression analyses suggested a role for ABC transporters and MFS transporters.

Keywords

Lignin biosynthesis; monolignol transport; plasma membrane; proteomics; transporter proteins

Published in

Journal of Experimental Botany
2020, Volume: 71, number: 20, pages: 6379-6395
Publisher: OXFORD UNIV PRESS