Genetically Engineering Stronger Poplar Tree Wood

SOPHIE BUSHWICK: We know trees play a big role in the fight against climate change. They soak up carbon dioxide from the air and store it for centuries in the form of biomass. But it turns out that trees could be doing even more. Last year, Science Friday covered how the company Living Carbon had genetically engineered poplar trees to grow twice as fast and store 30% more carbon than regular poplars.

Now, researchers at the University of Maryland have also dabbled in genetically modifying poplar trees. But they have a different goal. They’re aiming to make the woods stronger so it can be turned into lumber without the need for harsh chemical processing. This modification also helps the wood last longer without deteriorating, which lets the trees store carbon for longer periods of time.

Joining me to talk about this super wood is the lead plant geneticist of the study, Dr. Yiping Qi, Associate Professor at the Department of Plant Science and Landscape Architecture at the University of Maryland. Welcome to Science Friday. Thank you so much for joining us.

YIPING QI: Nice to meet you, Sophie.

SOPHIE BUSHWICK: Let’s get into this super wood. What is it and how do you genetically engineer trees to produce it?

YIPING QI: Sure. Yeah, I just want to give you a little background information. So a few years back, my colleague, Dr. Liangbing Hu in the Engineering College, he actually published a paper in Nature reporting engineering of super strong wood using chemical treatment.

So after chatting with him, so we kind of inspired to seek another more sustainable way, which is rather than using chemical to remove certain lignin in the wood material, we will genetically engineer the wood by editing one gene called 4CO1 in this case.

SOPHIE BUSHWICK: Just one gene?

YIPING QI: Yeah, just one gene. Because this gene is kind of– is coding for enzyme involving lignin biosynthesis pathway. So if we knock out this gene, we can affect this pathway. The plant, the tree will make less lignin. So this is our hypothesis.

So my lab is really good at genetic engineering and genome editing. So we just apply a technique called base editing to knock out this 4CO1 gene, specifically, in this case is poplar tree. So where we found that we can reduce about 13% of lignin content in poplar tree.

And this is a level, typically Dr. Hu’s lab going to be using chemical to remove this amount of lignin for engineering super strong wood. And then we went ahead to do the similar processing yet without doing any chemical treatment.

SOPHIE BUSHWICK: So wait, what is lignin? What does it normally do? And why does taking it out make the wood better?

YIPING QI: That’s a very good question. So lignin actually is a– is essentially one major part of the secondary sort of cell wall material from our wood, any wooden material, any trees, you will find them there. Different tree varieties have different content.

And they actually play an important role for structure and also filling the open space in the cell wall. But because different trees have different level lignin, because many processing of wood requires removal of lignin, so it’s kind of necessary to do lignin removal using chemicals when we processing, such as engineering, super strong wood.

SOPHIE BUSHWICK: And when you take it out, you’ve found that the wood is stronger. But also, you’ve mentioned that it stores extra carbon dioxide. How does that work? Why is the super wood better at trapping CO2?

YIPING QI: So the idea behind this carbon sequestration is many of the, you know, we grow forests, we grow lumber, and we use the lumber to do building construction and other materials. And the super strong wood is a promising sort of material, because it further engineered from natural wood.

Because of that, this wood is very strong and can resistant to a lot of deterioration environment. Can hence last much longer. So if we can have wood engineered stay there for much longer time without being sort of like degradated, going– releasing CO2 back to the atmosphere.

So in this case, we consider we have another way to really retain the– sort of fix the CO2 in the wood material. So in this way, we can sequester more carbon over time.

SOPHIE BUSHWICK: And you’ve done this genetic modification in poplar trees. Why did you choose to work with this kind of tree?

YIPING QI: Yeah, a very good question. So poplar tree is one of the major sort of research target or plant species we are using to understand the tree and also material. It is really– it can grow pretty well in the temperate environment in northern atmosphere. Not necessarily in the very hot environment where pine can thrive.

So the reason I’m using poplar is really for us to sort of using it as a model tree system, so that we– because it is amenable for genetic transformation. So the scientists like me, our lab can really work on them to modify genes rapidly to create a genome, engineer the trees, and assess their property. So with engineer like Dr. Hu. So this is really a model system. So once we have found something is working, in this case, we can expand other tree species.

SOPHIE BUSHWICK: And what do you see as the ultimate goal of this line of research?

YIPING QI: First of all, this research we just published is really just a proof of concept. And ultimately, what we want to do, we would actually expand this approach, this concept to the tree which are more relevant for us to use building material like pines, for example.

So if we can do that. then I think that will be– economically, that will be a lot of potential there. So this is really one major step for us to have this result. And we’re excited to really explore in other trees by applying similar technologies.

SOPHIE BUSHWICK: Thank you so much for joining us.

YIPING QI: You’re welcome.

SOPHIE BUSHWICK: That was Dr. Yiping Qi, Associate Professor at the Department of Plant Science and Landscape Architecture at the University of Maryland.

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