The role of plant extracellular vesicles in cell wall remodeling.

Lignin is an important component of plant cell walls, providing structural support and defense. Despite extensive research, the mechanisms underlying the transport and polymerization of lignin precursors remain poorly understood. Kankaanpää et al. have explored the role of extracellular vesicles (EVs) in lignin biosynthesis in Picea abies (Norway spruce). The authors identify key metabolites and enzymes involved in lignin biosynthesis and polymerization enriched in EVs from suspension cultures, suggesting a direct role for EVs in the transport and polymerization of lignin precursors. In addition, the presence of salicylic acid (SA) in EVs also highlights a novel synergy between lignin biosynthesis and plant defense mechanisms. This discovery challenges the traditional understanding of lignin biosynthesis by proposing that EVs act as mobile carriers, facilitating the localized polymerization of lignin in the cell wall. Further research is still needed to elucidate the exact nature of the EVs involved and the mechanisms of loading into and release from EVs. Nevertheless, these findings offer novel insights into the regulation of lignin biosynthesis and may have larger implications for agriculture and industrial applications.