On August 12, 2024, Professor Liangbing Hu (now at Yale University) and Professor Yiping Qi of the University of Maryland published a paper in the journal Matter in an interdisciplinary collaboration entitled “Genome-edited trees for high-performance engineered wood The paper “Genome-edited trees for high-performance engineered wood” was published in the journal Matter.
The research team achieved the manufacture of high-performance engineered wood without chemical treatment by applying gene editing techniques to reduce the lignin content of the wood. Dr. Yu Liu from Prof. Liangbing Hu's lab and Dr. Gen Li from Yiping Qi's lab are the co-first authors of the paper.
In the context of combating global climate change and environmental protection, alternatives to traditional building materials such as steel, concrete and plastics are receiving increasing attention. Engineered wood is one of the key choices due to its sustainability and high performance properties.
However, the traditional manufacturing process of engineered wood usually requires chemical methods to reduce the lignin content of the wood, which facilitates subsequent compression to enhance mechanical properties. This method not only consumes large amounts of energy and materials, but also generates a large amount of waste, which has a negative impact on the environment.
To address this problem, the research team proposed the creation of high-performance engineered wood that does not require chemical treatment by using gene editing to reduce the lignin content of the wood. Using a base editor called nCas9-A3A/Y130F, the team targeted the 4CL1 gene in poplar and successfully reduced the lignin content by introducing an early termination codon in the first exon sequence. This process resulted in a 12.8% reduction in lignin content.
To address this problem, the research team proposed the creation of high-performance engineered wood that does not require chemical treatment by using gene editing to reduce the lignin content of the wood. Using a base editor called nCas9-A3A/Y130F, the team targeted the 4CL1 gene in poplar and successfully reduced the lignin content by introducing an early termination codon in the first exon sequence. This process resulted in a 12.8% reduction in lignin content.
Gene-edited wood no longer needs to be chemically treated to enable the manufacture of compressed wood. The team succeeded in creating high-strength compressed wood by immersing the edited wood in water and thermally pressing it at high temperatures.
The results showed that the tensile strength of this gene-edited compressed wood reached 313.6 ± 6.4 MPa, which is comparable to that of the aluminum alloy 6061 and similar to that of the compressed wood after conventional chemical treatment. This indicates that the reduction of lignin content by gene editing can achieve comparable results to conventional chemical treatment and avoid the generation of waste by eliminating the need for chemical treatment.
Further studies also found that gene editing not only reduced the lignin content, but also had an effect on the structure of lignin. Through the analysis of Raman spectroscopy and 2D-HSQC NMR spectroscopy, the team found that the distribution of lignin in the cell walls of the wood changed, especially in the corners of the cells, where the lignin content was significantly reduced. This structural change helps the wood to form a denser structure during compression, which improves its mechanical properties.
The study also observed the microstructure of wood before and after gene editing by scanning electron microscopy (SEM), and the results showed that gene editing did not significantly change the microstructure of wood, such as the pore size of fiber cells, the diameter of the conduit and the thickness of the cell wall. This implies that the gene editing process had little effect on the physical properties of the wood, and only produced significant changes in lignin content and distribution.
During the experiment, the research team also compared the mechanical properties of gene-edited wood and compressed wood in the natural state. The results showed that the tensile strength of the gene-edited wood was significantly increased after compression, reaching 5.6 times that of the uncompressed wood, while the wood compressed by the traditional method was only increased by 2.6 times. The tensile strength of the compressed gene-edited wood was about 1.6 times higher than that of the wood compressed by the traditional method.
This research demonstrates the great potential of gene editing in wood engineering. Through gene editing technology, scientists are able to precisely regulate the lignin content and structure of wood to create high-performance wood products that meet different engineering needs. At the same time, this method also avoids the waste generated during chemical treatment, providing a more environmentally friendly and cost-effective way to manufacture engineered wood. In the future, with the further development of gene editing technology, the application prospect of engineered wood will be even broader, and it is expected to promote the sustainable development of building materials globally, reduce carbon dioxide emissions, and combat global climate change.
