Breeding to enrich lignin, a major component of lignocelluloses, in plants contributes to enhanced applications of lignocellulosic biomass into solid biofuels and valuable aromatic chemicals. To collect information on enhancing lignin deposition in grass species, important lignocellulose feedstocks, we generated rice (Oryza sativa) transgenic lines deficient in OsWRKY36 and OsWRKY102, which encode putative transcriptional repressors for secondary cell wall formation. We used CRISPR/Cas9-mediated targeted mutagenesis and closely characterized their altered cell walls using chemical and nuclear magnetic resonance (NMR) methods. Both OsWRKY36 and OsWRKY102 mutations significantly increased lignin content by up to 28 % and 32 %, respectively. Additionally, OsWRKY36/OsWRKY102-double-mutant lines displayed lignin enrichment of cell walls (by up to 41 %) with substantially altered culm morphology over the single-mutant lines as well as the wild-type controls. Our chemical and NMR analyses showed that relative abundances of guaiacyl and p-coumarate units were slightly higher and lower, respectively, in the WRKY mutant lignins compared with those in the wild-type lignins. Our results provide evidence that both OsWRKY36 and OsWRKY102 are associated with repression of rice lignification.

中文翻译：

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OsWRKY36 和 OsWRKY102 的双重敲除通过改变水稻秆形态促进木质化

育种以在植物中富集木质素（木质纤维素的主要成分）有助于增强木质纤维素生物质在固体生物燃料和有价值的芳香族化学品中的应用。为了收集有关增强草类（重要的木质纤维素原料）中木质素沉积的信息，我们生成了缺乏 OsWRKY36 和 OsWRKY102 的水稻（Oryza sativa）转基因品系，它们编码了用于次生细胞壁形成的假定转录抑制因子。我们使用 CRISPR/Cas9 介导的靶向诱变，并使用化学和核磁共振 (NMR) 方法密切表征它们改变的细胞壁。OsWRKY36 和 OsWRKY102 突变均使木质素含量分别显着增加了 28% 和 32%。此外，OsWRKY36/OsWRKY102-双突变系显示出细胞壁的木质素富集（高达 41%），与单突变系和野生型对照相比，秆形态发生了显着改变。我们的化学和核磁共振分析表明，与野生型木质素相比，WRKY 突变体木质素中愈创木脂基和对香豆酸单位的相对丰度分别略高和略低。我们的结果提供证据表明 OsWRKY36 和 OsWRKY102 都与水稻木质化的抑制有关。