Contact: Steve Karlen, (608) 262-1629, [email protected];
John Ralph, (608) 890-2429, [email protected]
Madison – When scientists reported in 2014 that they had successfully engineered a poplar plant “designed for deconstruction,” the finding made international news. The highly degradable poplar, the first of its kind, could substantially reduce the energy use and cost of converting biomass to a number of products, including biofuels, pulp and paper.
Now, some of those same researchers are reporting a surprising new revelation. As University of Wisconsin-Madison biochemistry Professor John Ralph puts it, “Nature was already doing what we thought we’d laboriously taught her to do.”
To make the hybrid poplar, Ralph, Shawn Mansfield, Curtis Wilkerson, and other Great Lakes Bioenergy Research Center (GLBRC) researchers had incorporated an exotic gene conferring weak bonds into the plant’s lignin, the hard-to-process compound that gives plant cell walls their sturdiness but makes them difficult to process in an industrial setting. The resulting lignin, dubbed zip-lignin, readily breaks down under simple chemical conditions.
This new GLBRC-led study, published Friday (Oct. 14, 2016) in Science Advances, shows that those poplar trees and many other plants from all over the phylogenetic tree have actually evolved to naturally produce zip-lignin. In other words, not only can we potentially breed for degradability in plants, but humans may have been doing just that – selecting certain plants for easier processing – for thousands of years.
“We didn’t know the plants were making the native zip because we couldn’t detect it,” says Steve Karlen, a research scientist at UW-Madison and the paper’s lead author. “When we added the new gene we thought we were adding functionality, but we were actually increasing what was already there.”