Department of Biology, Syracuse University, Syracuse, NY, USA.
Plant Biotechnol J. 2012 Sep;10(7):883-9. doi: 10.1111/j.1467-7652.2012.00714.x. Epub 2012 Jun 2.
Hybrid poplar (Populus tremula X P. alba) genetically engineered to express the pine cytosolic glutamine synthetase gene (GS1a) has been previously shown to display desirable field performance characteristics, including enhancements in growth and nitrogen use efficiency. Analysis of wood samples from a 3-year-old field trial of three independently transformed GS1a transgenic hybrid poplar lines revealed that, when compared with wild-type controls, ectopic expression of GS1a resulted in alterations in wood properties and wood chemistry. Included were significant enhancements in wood fibre length, wood density, microfibre angle, per cent syringyl lignin and elevated concentrations of wood sugars, specifically glucose, galactose, mannose and xylose. Total extractive content and acid-insoluble lignin were significantly reduced in wood of GS1a transgenics when compared with wild-type trees. Together, these cell wall characteristics resulted in improved wood pulping attributes, including improved lignin solubilization with no concurrent decrease in yield. Trees with increased GS1a expression have improved characteristics for pulp and paper production and hold potential as a feedstock for biofuels production.
已证实，表达松树细胞质谷氨酰胺合成酶基因（GS1a）的杂交杨树（Populus tremula X P. alba）在田间具有理想的表现特性，包括生长和氮利用效率的提高。对来自三个独立转化的 GS1a 转基因杂交杨树品系的 3 年野外试验的木材样本进行分析表明，与野生型对照相比，GS1a 的异位表达导致木材性质和木材化学发生改变。包括木材纤维长度、木材密度、微纤维角度、愈创木酚木质素百分比和升高的木材糖浓度（特别是葡萄糖、半乳糖、甘露糖和木糖）的显著提高。与野生型树木相比，GS1a 转基因木材的总提取物含量和酸不溶性木质素显著降低。这些细胞壁特性共同导致了制浆属性的改善，包括木质素的更好溶解，而不伴随产量下降。具有增加的 GS1a 表达的树木具有改善的纸浆和纸张生产特性，并有可能成为生物燃料生产的原料。
