Hu W J, Harding S A, Lung J, Popko J L, Ralph J, Stokke D D, Tsai C J, Chiang V L
Plant Biotechnology Research Center, School of Forestry and Wood Products, Michigan Technological University, Houghton, MI 49931, USA.
Nat Biotechnol. 1999 Aug;17(8):808-12. doi: 10.1038/11758.
Because lignin limits the use of wood for fiber, chemical, and energy production, strategies for its downregulation are of considerable interest. We have produced transgenic aspen (Populus tremuloides Michx.) trees in which expression of a lignin biosynthetic pathway gene Pt4CL1 encoding 4-coumarate:coenzyme A ligase (4CL) has been downregulated by antisense inhibition. Trees with suppressed Pt4CL1 expression exhibited up to a 45% reduction of lignin, but this was compensated for by a 15% increase in cellulose. As a result, the total lignin-cellulose mass remained essentially unchanged. Leaf, root, and stem growth were substantially enhanced, and structural integrity was maintained both at the cellular and whole-plant levels in the transgenic lines. Our results indicate that lignin and cellulose deposition could be regulated in a compensatory fashion, which may contribute to metabolic flexibility and a growth advantage to sustain the long-term structural integrity of woody perennials.
由于木质素限制了木材在纤维、化学和能源生产方面的应用，因此下调木质素的策略备受关注。我们培育了转基因杨树（颤杨），其中编码4-香豆酸：辅酶A连接酶（4CL）的木质素生物合成途径基因Pt4CL1的表达通过反义抑制被下调。Pt4CL1表达受抑制的树木木质素含量降低了45%，但纤维素含量增加了15%，从而得到了补偿。结果，木质素-纤维素的总量基本保持不变。转基因株系的叶、根和茎的生长显著增强，并且在细胞和整株水平上都维持了结构完整性。我们的结果表明，木质素和纤维素的沉积可以以一种补偿方式进行调节，这可能有助于代谢灵活性和生长优势，以维持多年生木本植物的长期结构完整性。
