Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan.
Department of Botany, University of British Columbia, Vancouver, BC, Canada.
Curr Opin Biotechnol. 2019 Apr;56:75-81. doi: 10.1016/j.copbio.2018.10.001. Epub 2018 Oct 22.
The final step of lignin biosynthesis is the polymerization of monolignols in apoplastic cell wall domains. In this process, monolignols secreted by lignifying cells, or occasionally neighboring non-lignifying and/or other lignifying cells, are activated by cell-wall-localized oxidation systems, such as laccase/O and/or peroxidase/HO, for combinatorial radical coupling to make the final lignin polymers. Plants can precisely control when, where, and which types of lignin polymers are assembled at tissue and cellular levels, but do not control the polymers' exact chemical structures per se. Recent studies have begun to identify specific laccase and peroxidase proteins responsible for lignin polymerization in specific cell types and during different developmental stages. The coordination of polymerization machinery localization and monolignol supply is likely critical for the spatio-temporal patterning of lignin polymerization. Further advancement in this research area will continue to increase our capacity to manipulate lignin content/structure in biomass to meet our own biotechnological purposes.
木质素生物合成的最后一步是单体酚在质外体细胞壁区域的聚合。在此过程中，木质素形成细胞分泌的单体酚，或者偶尔是相邻的非木质素形成细胞和/或其他木质素形成细胞，被定位于细胞壁的氧化系统（如漆酶/O 和/或过氧化物酶/HO）激活，进行组合自由基偶联，形成最终的木质素聚合物。植物可以精确控制在组织和细胞水平上何时、何地以及组装哪种类型的木质素聚合物，但不能控制聚合物的精确化学结构本身。最近的研究开始确定特定的漆酶和过氧化物酶蛋白，这些蛋白负责特定细胞类型和不同发育阶段的木质素聚合。聚合机制定位和单体酚供应的协调对于木质素聚合的时空模式至关重要。该研究领域的进一步进展将继续提高我们操纵生物质中木质素含量/结构的能力，以满足我们自己的生物技术目的。
