Abstract：
Miscanthus is a perennial grass suitable for the production of lignocellulosic biomass on marginal lands. The effects of salt stress on Miscanthus cell wall composition and its consequences on biomass quality have nonetheless received relatively little attention. In this study, we investigated how exposure to moderate (100 mM NaCl) or severe (200 mM NaCl) saline growing conditions altered the composition of both primary and secondary cell wall components in the stems of 15 Miscanthus sinensis genotypes. The exposure to stress drastically impacted biomass yield and cell wall composition in terms of content and structural features. In general, the observed compositional changes were more pronounced under severe stress conditions and were more apparent in genotypes with a higher sensitivity towards stress. Besides a severely reduced cellulose content, salt stress led to increased pectin content, presumably in the form of highly branched rhamnogalacturonan type I. Although salt stress had a limited effect on the total lignin content, the acid-soluble lignin content was strongly increased in the most sensitive genotypes. This effect was also reflected in substantially altered lignin structures and led to a markedly reduced incorporation of syringyl subunits and p-coumaric acid moieties. Interestingly, plants that were allowed a recovery period after stress ultimately had a reduced lignin content compared to those continuously grown under control conditions. In addition, the salt stress-induced cell wall alterations contributed to an improved enzymatic saccharification efficiency.
摘要：
芒草是一种多年生草，适合在边缘土地上生产木质纤维素生物质。尽管如此，盐胁迫对芒草细胞壁组成的影响及其对生物量质量的影响却很少受到关注。在这项研究中,我们研究了暴露于中度（100mMNaCl）或重度（200mMNaCl）盐水的生长条件如何改变15种芒草基因型茎中原代和次生细胞壁成分的组成。在含量和结构特征方面，暴露于胁迫极大地影响了生物量产量和细胞壁组成。总的来说,观察到的成分变化在严重胁迫条件下更为明显，并且在对胁迫敏感性较高的基因型中更为明显。除了严重降低的纤维素含量，盐胁迫导致果胶含量增加，推测为I型高分支鼠李糖半乳糖醛酸的形式，尽管盐胁迫对总木质素含量的影响有限，在最敏感的基因型中，酸溶性木质素含量大大增加。这种作用也反映在木质素结构的基本改变中，并导致丁香亚基和对香豆酸部分的掺入显着减少。有趣的是,与在对照条件下连续生长的植物相比，在胁迫后允许恢复期的植物最终具有降低的木质素含量。此外,盐胁迫诱导的细胞壁改变有助于提高酶促糖化效率。
