Lignin Complexity and Flexibility: How and Why Do Grasses Produce Lignins Different from Woods?

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会议名称:“2022世界木材日”研讨会暨第四届国际林联(IUFRO)林产品文化研究组讨论会
会议时间:2022年3月21日

报告嘉宾:Yuki Tobimatsu
嘉宾简介:日本京都大学生存圈研究所副教授

摘要:

Monocotyledonous grasses have evolved unique cell wall structures distinctively different from those of typical wood species, i.e., eudicots (hardwood) and gymnosperms (softwood). As a prime example, grasses produce lignins highly decorated by hydroxycinnamates (p-coumaroylates and ferulates) and flavonoid tricin units by incorporating grass-specific lignin monomers, i.e., γ-acylated monolignols and a flavone tricin, alongside canonical monolignols for cell wall lignification, which contrasts typical eudicot and gymnosperm species that utilize monolignols as sole lignin monomers. Currently, it remains largely unknown how such grass-specific lignin monomers are biosynthesized and function in grass cell walls. Moreover, how the existence of the grass-specific lignin decorations affects the utility of grass biomass remains poorly understood. In this context, our group has been investigating the biosynthesis of the grass-specific lignin monomers and exploring bioengineering approaches to produce transgenic grass plants with altered lignin decoration units. In this presentation, I will briefly summarize our recent findings regarding the biosynthesis of the lignin-associated hydroxycinnamates and flavonoid tricin in rice, a model grass species and an economically important grass crop, and structure and property characterizations of transgenic rice plants that produce cell walls lacking grass-specific lignin decorations. Deepening our understanding of the biosynthesis and properties of grass cell walls may contribute to better understanding of the nature and evolution of wood cell walls.

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