Nacogdoches researchers sequence DNA to understand Chinese tallow leaf destruction

Oct 26, 2015

A wildlife biologist with the U.S. Forest Service Southern Research Station in Nacogdoches is working with a Stephen F. Austin State University biotechnologist sequencing DNA in pond water to better understand the devastating effects of the invasive Chinese tallow tree overrunning native habitats in the Deep South.

Stephen F. Austin State environmental science graduate student Ray Montez extracts a water sample from an experiment pool containing Chinese tallow leaf litter.
Credit Daniel Saenz

When the Chinese tallow tree’s leaves fall into water, oxygen is depleted and the water is acidified. It makes it hard for fish to survive, according to U.S. Forest Service wildlife biologist Daniel Saenz, who started this research in 2008. He says it’s hard to stop Chinese tallow.

“They’re really, really fast growers. They grow so fast that they outcompete everything else for the light,” Saenz said, who sees them grow up when an opening emerges in forestland.

Saenz wants to learn exactly what chemicals are produced in the water by the tree’s fallen leaves. He sent pond water samples to a special DNA lab and the raw data, he says, should be back within days.

“What we’ll have is a terabyte of data, which is all the sequences. The wrangling of the data is one of the more challenging parts and not the part that I’m very good at,” Saenz said. “That’s why we have the collaboration with people who are better at doing this.”

Enter SFA biotechnology professor Alexandra Martynova-Van Kley. Bacteria are akin to factories, she says. They specialize in certain chemicals, and release other chemicals into the environment. Through this massive sequencing project, Martynova-Van Kley can solve the mystery of what’s growing in the pond water.

Just looking at the bacteria in sequencing the samples, this is very new. Literally, with this research no one had ever done this before,” Martynova-Van Kley said.

She asserts DNA sequencing might be helpful for better understanding other invasive plants, like giant salvina.

“We actually can see each DNA present in the sample. If you take a water sample and read all the DNA there, it’s a snapshot or fingerprint of communities of bacteria in the water,” Martynova-Van Kley said.

She expects to publish the findings on the Chinese tallow tree in scientific journals.