University of Missouri discover how poplar changes its wood chemistry based on climate

In Missouri, a new study led by researchers at the University of Missouri has uncovered how poplar trees can naturally adjust a key part of their wood chemistry based on changes in their environment. This discovery — the result of a collaboration with scientists at Oak Ridge National Laboratory and the University of Georgia — could help create better biofuels and other sustainable products.

The researchers examined 430 wood samples from Populus trichocarpa, a poplar tree species that grows primarily in western North America from northern California to British Columbia in Canada. The trees growing in warmer climates produced lignin with a higher ratio of syringyl-to-guaiacyl (S/G) — two key chemical building blocks called monomers — compared with those from colder climates.

In addition to the genetic study, the research team used 3D computer modeling to better understand their findings.

To the team’s surprise, the mutation didn’t show up within the active center of the protein — suggesting that the deposition of lignin in natural settings may be regulated by still uncharacterized signaling pathways.

In another unexpected discovery, the team found trace levels of a rare form of lignin — called C-lignin — in poplar trees. Previously, C-lignin was only known to be present in the seeds of a few plants, such as vanilla and cacti.

Because C-lignin is simpler and more uniform than regular lignin, it’s easier to break down and process into usable plant material for bioplastics, biofuels and other renewable products.

Looking ahead, Mizzou’s team is now working to genetically engineer poplar trees and soybeans so that they can contain more C-lignin — making the biomass of these plants easier to process into next-generation biorefineries.