Genetically Edited Wood

Timothy Sedlak - July 15, 2023

Researchers have made significant progress in developing genetically edited poplar trees with reduced lignin content using CRISPR gene-editing tools. Lignin, a woody substance found in trees, poses environmental challenges in papermaking processes, leading to chemical waste and greenhouse gas emissions. By targeting genes associated with lignin production, the engineered poplar trees exhibited a 49.1% reduction in lignin content and a 228% increase in cellulose-to-lignin ratio, potentially revolutionizing the paper industry.

In the papermaking process, lignin must be separated from cellulose fibers to produce paper. Previous attempts to breed and engineer trees with lower lignin content have yielded limited success. However, the application of CRISPR gene editing allowed researchers at North Carolina State University (NC State) to explore simultaneous changes in multiple poplar genes involved in lignin production.Through computer modeling and extensive gene-editing combinations, the team identified 347 alterations that could enhance cellulose production, reduce lignin content, or achieve both objectives simultaneously. Subsequently, they implemented gene edits associated with the most promising combinations, resulting in engineered poplar trees grown in a greenhouse.

After six months, the engineered trees displayed a remarkable 49.1% reduction in lignin content and a significant increase in cellulose-to-lignin ratio. If utilized in a typical paper mill, these modified varieties could increase paper output by 40%, reduce greenhouse gas emissions by 20%, and potentially generate approximately $1 billion in lifetime profits.Although the findings show promising results, further research and field trials are necessary to ensure the engineered poplar trees can withstand real-world conditions and reach maturity successfully. Field trials will also help evaluate their growth volume compared to regular poplars.

Moreover, regulatory approval is required before implementing genetically edited trees. Notably, the CRISPR-edited poplar trees do not contain transgenes from other organisms, simplifying the regulatory pathway, particularly in the United States.The researchers, who have founded a spin-off company called TreeCo, aim to commence field trials of CRISPR-edited poplars promptly. They are also exploring the application of similar gene edits in eucalyptus and pine trees, which are extensively used in paper production.

The development of genetically edited trees with reduced lignin content through CRISPR gene editing technology represents a significant step toward sustainable paper production. It holds the potential to minimize environmental impact, lower pollution associated with paper mills, and contribute to the industry's long-term profitability while promoting a more eco-friendly approach to paper manufacturing.

Reference: Vânia G. Zuin Zeidler, Genetic editing of wood for sustainability.Science381,124-125(2023).DOI:10.1126/science.adi8186