Genetic editing of wood for sustainability

Despite the importance of wood fibers to meet the growing demand for renewable tissue, paper, packaging, textile, and other fiber products, wood fiber production has been less efficient and productive than researchers have hoped. Now, CRISPR editing has enabled scientists to design wood in which lignin – which must be cleaved and dissolved so fiber production can take place – is more suitable for fiber production. “The edited wood alleviates a major fiber-production bottleneck … and could bring unprecedented operational efficiencies, bioeconomic opportunities, and environmental benefits,” say the study’s authors. The ability to isolate fibers from wood is largely determined by the content and composition of lignin, a biopolymer recalcitrant to chemical and enzymatic degradation. More than five decades of research have extensively investigated the individual components of lignin biosynthesis. However, these efforts have predominantly focused on the modification of single genes or gene families. Here, Daniel Sulis and colleagues show that strategic multiplex CRISPR editing of monolignol biosynthesis genes improves wood properties beyond what can be achieved by editing single genes or gene families. The authors used their approach to generate modified wood composition in a species of poplar tree, where CRISPR editing increased the wood carbohydrate-to-lignin ratio up to 228% that of wild type, which sets the stage for more efficient fiber pulping. In a related Perspective, Vânia G. Zuin Zeidler discusses how trees engineered to have less lignin could make paper production less polluting.