Down-regulation of OsMYB103L distinctively alters beta-1,4-glucan polymerization and cellulose microfibers assembly for enhanced biomass enzymatic saccharification in rice

Biotechnology for Biofuels

Mingliang Zhang¹  Tao Xia²  Jingyang Li³  Hailang Wang⁴  Liangcai Peng⁴  Ran Zhang⁴  Zhen Hu⁴  Yanting Wang⁴  Youmei Wang⁴  Leiming Wu⁵  Lingqiang Wang⁶  Haizhong Yu⁷  Zi Luo⁸  Lin Li⁸ 

[1] Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;College of Life Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, 570102, Haikou, China;Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts & Science, Xiangyang, China;Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China;Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts & Science, Xiangyang, China;College of Life Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, 430070, Wuhan, China;State Key Laboratory for Conservation & Utilization of Subtropical Agro-Bioresources, College of Agriculture, Guangxi University, Nanning, China;Laboratory of Biomass Engineering & Nanomaterial Application in Automobiles, College of Food Science & Chemical Engineering, Hubei University of Arts & Science, Xiangyang, China;National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China;

关键词: Cellulose synthesis;    Cellulose polymerization;    Microfibril assembly;    OsMYBs;    Multi-omics;    Biomass saccharification;    Fragile culm;    Rice;   

DOI  :  10.1186/s13068-021-02093-8

来源: Springer

【 摘 要 】

BackgroundAs a major component of plant cell walls, cellulose provides the most abundant biomass resource convertible for biofuels. Since cellulose crystallinity and polymerization have been characterized as two major features accounting for lignocellulose recalcitrance against biomass enzymatic saccharification, genetic engineering of cellulose biosynthesis is increasingly considered as a promising solution in bioenergy crops. Although several transcription factors have been identified to regulate cellulose biosynthesis and plant cell wall formation, much remains unknown about its potential roles for genetic improvement of lignocellulose recalcitrance.ResultsIn this study, we identified a novel rice mutant (Osfc9/myb103) encoded a R2R3-MYB transcription factor, and meanwhile generated OsMYB103L-RNAi-silenced transgenic lines. We determined significantly reduced cellulose levels with other major wall polymers (hemicellulose, lignin) slightly altered in mature rice straws of the myb103 mutant and RNAi line, compared to their wild type (NPB). Notably, the rice mutant and RNAi line were of significantly reduced cellulose features (crystalline index/CrI, degree of polymerization/DP) and distinct cellulose nanofibers assembly. These alterations consequently improved lignocellulose recalcitrance for significantly enhanced biomass enzymatic saccharification by 10–28% at p < 0.01 levels (n = 3) after liquid hot water and chemical (1% H2SO4, 1% NaOH) pretreatments with mature rice straws. In addition, integrated RNA sequencing with DNA affinity purification sequencing (DAP-seq) analyses revealed that the OsMYB103L might specifically mediate cellulose biosynthesis and deposition by regulating OsCesAs and other genes associated with microfibril assembly.ConclusionsThis study has demonstrated that down-regulation of OsMYB103L could specifically improve cellulose features and cellulose nanofibers assembly to significantly enhance biomass enzymatic saccharification under green-like and mild chemical pretreatments in rice. It has not only indicated a powerful strategy for genetic modification of plant cell walls in bioenergy crops, but also provided insights into transcriptional regulation of cellulose biosynthesis in plants.

【 授权许可】

CC BY