Wild type poplar hybrid (Populus alba × P. glandulosa cv‘84k′), p ‐coumaroyl shikimate 3′‐hydroxylase (C3H) downregulated transgenic poplar and hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) downregulated transgenic poplar were used as experimental materials. The techniques of two‐dimensional heteronuclear single‐quantum coherence nuclear magnetic resonance (2D‐HSQC‐NMR) spectroscopy and pyrolysis coupled to gas chromatography‐mass spectrometry (Py‐GC/MS) were used for the analysis and comparison of the lignin structure and monomer ratio between the wild type poplar hybrid and transgenic plants. The results of these analyses showed that the lignin of all poplar samples contained β ‐O ‐4′ aryl ether linkages and their derivative substructures, resinol substructures, spirodienone substructures, phenylcoumarane substructures, p ‐hydroxycinnamyl alcohol end groups, syringyl units, p ‐hydroxyphenyl units, guaiacyl units, p ‐hydroxybenzoate substructures, and ferulate. Downregulation of C3H and HCT in double transgenic poplar reduced the β ‐O ‐4′ relative content of lignin in poplar. The S unit, H unit, and S/G ratio in the C3H‐ downregulated transgenic poplar were increased, while its G unit was decreased. The S unit and S/G ratio in HCT‐ downregulated transgenic poplar were decreased while its G unit was increased. The C3H‐ downregulated transgenic poplar was a superior material for biomass energy, pulping, and papermaking than the HCT‐ downregulated transgenic poplar.

中文翻译：

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C3H和HCT RNAi转基因杨树幼树中木质素的结构和单体比

野生型白杨杂交种（Populus alba×P. glandulosa cv'84k'），p-香豆酰sh草酸酯3'-羟化酶（C3H）下调的转基因杨树和羟肉桂酸CoA：mate草酸酯的羟肉桂酸转移酶（HCT）下调的转基因杨树用作实验材料。二维异核单量子相干核磁共振（2D-HSQC-NMR）光谱和热解技术与气相色谱-质谱（Py-GC / MS）结合用于分析和比较木质素结构和野生型杨树杂种与转基因植物之间的单体比。这些分析的结果表明，所有杨树样品中的木质素均含有β - O‐4'芳基醚键及其衍生物亚结构，树脂醇亚结构，螺二烯酮亚结构，苯基香豆烷亚结构，对羟基肉桂醇端基，丁香基单元，对羟基苯酚单元，愈创木基单元，对羟基苯甲酸酯亚结构和阿魏酸酯。双转基因杨树中C3H和HCT的下调降低了杨树中木质素的β - O-4 '相对含量。在S单元，H单元，并且在C3H S / G比值-下调的转基因杨树均升高，而其G单位降低。在HCT在S单元和S / G比值-同时其G单位增加下调的转基因杨树均降低。在C3H -下调的转基因杨树是生物质能优良材料，制浆，造纸比HCT -下调的转基因杨树。