Nature Biotechnology
17, 808 - 812 (1999)
doi:10.1038/11758
Repression of lignin biosynthesis promotes cellulose accumulation and
growth in transgenic treesWen-Jing Hu1, 4, Scott A. Harding1, Jrhau Lung1, Jacqueline L. Popko1, John Ralph2, Douglas D. Stokke3, Chung-Jui Tsai1
& Vincent L. Chiang11
Plant Biotechnology Research Center, School of Forestry
and Wood Products, Michigan Technological University, Houghton
, MI 49931. 2
US Dairy Forage Research Center, USDA-Agricultural
Research Service and Department of Forestry, University of Wisconsin-Madison
, Madison, WI 53706. 3
Department of Forestry, Iowa State University,
Ames, IA 50011. 4
Current address: Department of Pediatrics, Baylor College
of Medicine, Houston, TX 77030.
Correspondence should be addressed to Vincent L. Chiang vchiang@mtu.eduplant genetic engineeringlignin biosynthesis4CLtransgenicPopulus tremuloidesBecause 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.
|
