If you’ve seen headlines of tomatoes with a spicy kick and mushrooms that won’t brown, it comes as no surprise genetic engineering is providing a means for us to reshape nature in ways that would otherwise be nigh impossible.
Scientists like Rodolphe Barrangou and Jack Wang of North Carolina State University (NC State) weren’t looking to reshape a fruit or vegetable. They had their eyes and genetic engineering tools on the trillions of organisms that make up the very fabric of nature: Trees.
Sprucing up our oxygen-givers is an ambitious endeavor that’s been over a decade in the making for the two scientists. Now, they have something to show for it: a genetically modified poplar tree. In a study published Thursday in the journal Science, Barrangnou, Wang, and collaborators from within NC State, Illinois, and China describes what it took to make this genetically-engineered tree, which contains less lignin, a branching material (also known as a polymer) that makes plants rigid and gives wood it’s hard quality than a typical tree would have.
The researchers say this could be a first step toward building sustainability within the lumber and fiber industry, which could potentially offset climate change.
“All organisms on land depend on trees to survive, and trees are also intimately associated with pretty much all aspects of society and daily life,” Wang tells Inverse. “It’s critical we develop ways to improve the quality and the resilience of forest trees that can meet the demands that we rely on for our everyday lives.”
A little help from AI
The idea of changing a tree’s genome for environmental purposes isn’t exactly novel. Early this year, biotechnology start-up Living Carbon, based in San Franciso, began planting saplings that are a hybrid of two European poplars in southern Georgia. China, on the other hand, has been planting genetically modified poplar trees in commercial plantations since 2002.
Barrangou and Wang wanted to focus on lignin when genetically altering their poplar trees, whose wood is often used for construction-grade lumber along with pulp and paper products. Trees contain a mix of different polymers, lignin among them. This material is considered a bit of a waste product since it makes it hard to extract components like cellulose fibers from wood needed for pulp and paper production.
But reducing a tree’s lignin content isn’t simple — Barrangou says in some ways, genetically modifying a plant genome can be even more difficult than a human genome.
However, the researchers had an ace up their sleeve. For the last several years, Wang’s lab has been creating genetic catalogs of various trees, poplar included. Alongside the genetic catalogs, they were designing machine-learning models that would help in the decision-making of which genes to play around with.
“That vast amount of genetic, biochemical, transcriptomic, proteomic, and metabolomic data [we uncovered] enables the computer to device different combinations of genome editing strategies that would allow us to alter the lignin composition,” Barrangou tells Inverse.
Initially, the computer came up with 70,000 potential solutions involving genes tied to lignin production, although only about five percent of those would actually be helpful. Of that five percent, the researchers went with seven strategies that promised to reduce the lignin content by 35 percent compared to naturally-grown poplar trees, increase the carbohydrate-to-lignin ratio by 200 percent, and increase the ratio of syringyl and guaiacyl (building blocks of lignin) by 200 percent. The rate at which the tree grew would remain unchanged.
Poplar tree cells were altered with the gene-editing tool CRISPR and around 174 seedlings were planted in NCSU’s greenhouse. After six months of growing (up to a soaring ten feet, says Barrangou), the researchers examined the trees. The modified poplars had up to 50 percent less lignin in some varieties, as well as a 228 percent increase in the carbohydrate to lignin in others.
Gene editing our way out of climate change
Barrangou and Wang say improving the lignin content of trees will be a big boost to industries that process wood and use it for various applications.
“What we found was when you replace the current [poplar] wood with our CRISPR wood, the model shows it could… potentially increase the capacity for production by upwards of 30 to 40 percent, a sustainable improvement,” says Wang.
The CRISPR-modified trees may also offset the carbon footprint of these lumber and adjacent industries by up to 20 percent, the study also found.
The researchers hold hope genetically engineering trees could help with climate change mitigation down the line. Trees are considered “carbon sinks” for their ability to take carbon from the air and store it inside their wood, the plant matter around them, and the soil. If we can somehow turbocharge this ability, we could build impressive carbon sinks around the world just by planting genetically modified trees.
“The pace at which we’re not meeting our [climate goals], the pace at which we’re not meeting our milestones should increase our sense of urgency to deploy CRISPR for sustainable forestry,” says Barrangou. “Whether you’re a scientist, an investor, or someone in the public, we should have an increased sense of awareness of our responsibility, if not duty, to deploy this technology to address those greater challenges right now.”
