Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation, Ministry of Education & Hubei Province, Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
Int J Biol Macromol. 2024 Mar;262(Pt 2):130137. doi: 10.1016/j.ijbiomac.2024.130137. Epub 2024 Feb 12.
Crop straws provide enormous biomass residues applicable for biofuel production and trace metal phytoremediation. However, as lignocellulose recalcitrance determines a costly process with potential secondary waste liberation, genetic modification of plant cell walls is deemed as a promising solution. Although pectin methylation plays an important role for plant cell wall construction and integrity, little is known about its regulation roles on lignocellulose hydrolysis and trace metal elimination. In this study, we initially performed a typical CRISPR/Cas9 gene-editing for site mutations of OsPME31, OsPME34 and OsPME79 in rice, and then determined significantly upgraded pectin methylation degrees in the young seedlings of three distinct site-mutants compared to their wild type. We then examined distinctively improved lignocellulose recalcitrance in three mutants including reduced cellulose levels, crystallinity and polymerization or raised hemicellulose deposition and cellulose accessibility, which led to specifically enlarged biomass porosity either for consistently enhanced biomass enzymatic saccharification under mild alkali pretreatments or for cadmium (Cd) accumulation up to 2.4-fold. Therefore, this study proposed a novel model to elucidate how pectin methylation could play a unique enhancement role for both lignocellulose enzymatic hydrolysis and Cd phytoremediation, providing insights into precise pectin modification for effective biomass utilization and efficient trace metal exclusion.
秸秆提供了巨大的生物质残余物，可用于生物燃料生产和痕量金属的植物修复。然而，由于木质纤维素的抗降解性决定了这是一个成本高昂的过程，并且可能会释放出潜在的二次废物，因此对植物细胞壁进行遗传修饰被认为是一种有前途的解决方案。尽管果胶甲基化对于植物细胞壁的构建和完整性起着重要作用，但人们对其在木质纤维素水解和痕量金属去除方面的调节作用知之甚少。在本研究中，我们首先对水稻中的 OsPME31、OsPME34 和 OsPME79 进行了典型的 CRISPR/Cas9 基因编辑，以实现特定位点的突变，然后确定了三个不同突变体的幼苗中果胶甲基化程度显著提高，与野生型相比。然后，我们在三个突变体中检查了明显改善的木质纤维素抗降解性，包括降低纤维素水平、结晶度和聚合度，或提高半纤维素沉积和纤维素可及性，这导致生物质孔隙率显著增大，无论是在温和碱预处理下生物质酶解的一致性提高，还是镉（Cd）积累高达 2.4 倍。因此，本研究提出了一个新的模型来阐明果胶甲基化如何对木质纤维素的酶解和 Cd 的植物修复起到独特的增强作用，为精确的果胶修饰提供了深入的了解，以实现有效的生物质利用和有效的痕量金属排除。
