Bioorthogonal Tracking of Spatiotemporal Lignification Dynamics in Plant Cell Walls Using Alkyne-Tagged Glycosylated Monomers

Abstract

Lignin, a major component of plant cell walls, plays a critical role in structural support and stress resistance. Despite its importance, the transport and deposition dynamics of the glycosylated lignin monomer during lignification in living cells remain poorly understood, hindering advances in biomass utilization. To address this challenge, alkyne-labeled glycosylated lignin precursors (pGCA ALK and CF ALK ) were synthesized by introducing propargyl groups at the ortho position of aromatic rings. These precursors were successfully incorporated into lignin polymers in flax (a herbaceous plant) and ginkgo (a gymnosperm), enabling the real-time tracking of lignification via fluorescent click chemistry. Quantitative imaging revealed that lignification initiates at cell corners and the middle lamella and then progressively extends into secondary cell walls. Distinct deposition patterns were observed: parenchyma cells exhibited continuous lignin accumulation, whereas fiber tracheids underwent rapid lignification, followed by cell death. Specialized pit structures displayed "tunnel-like" lignin deposition in longitudinal pits and unilateral patterns in transverse pits. In vitro synthesis of dehydrogenation polymers (DHP) and extraction of the cellulolytic enzyme lignin (CEL) from ginkgo confirmed the biocompatibility of labeled monomers. LC-MS analysis further demonstrated that alkynyl groups formed oxygen-containing cyclic structures without disrupting natural β-O-4 and β-5 lignin linkages. Application of this labeling method in biomass utilization indicated that lower overall fluorescence intensity correlates with more efficient lignin removal during pretreatment. These results provide new insights into the spatiotemporal dynamics of lignification and establish a bioorthogonal platform for lignin research, offering promising strategies for optimizing plant biomass in industrial applications.

Plant phenotyping relevance

蛍光クリック化学による生細胞内リグニン形成の時空間追跡と定量イメージング手法を開発・適用しており、植物状態の取得方法が研究の中心である。

Code and data availability

公開本文の所在を確認できませんでした。非公開または購読が必要な可能性があります。

No evidence-backed public reproduction asset is currently recorded.