Aaron Liepman's lab is part of a United States Department
of Agriculture project that could someday lead to more
efficient production of everything from biofuels to beer.
Current ethanol production relies on plants like corn
and sugar cane. One goal of Liepman's research is to expand
the range of crops used for biofuels to eventually include
energy crops specifically engineered for the job.
For the past several years, Liepman's research has focused
on families of genes, called cellulose synthase-like (CSL)
sequences, which tells proteins what kind of carbohydrates
to make in the plant cell wall. Scientists think there
are hundreds of CSLs, though only a handful of the enigmatic
genes have been studied to date.
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Liepman |
"Hopefully, this research will provide insight about
the carbohydrates produced by various plant proteins,"
said Liepman, an Eastern Michigan University biologist. "Eventually,
that knowledge can be harnessed to help us control the
composition of plant cell walls. But, before we can
control this process, we need to understand it. We're
at the understanding stage right now. Or, rather, the
trying to understand stage."
Liepman's lab is adding to that body of knowledge by drawing
connections between different CSL families and the production
of various plant cell wall carbohydrates. In the long
term, this research will help scientists develop plants
better suited to certain needs, and the applications range
far beyond biofuel.
The carbohydrates in question also affect things like
properties of wood pulp, the mechanics of textile fibers
and the health effects of dietary fiber.
One CSL family, for example, is associated with a heart-healthy
carbohydrate called Beta-glucan that's found in grains.
Genetically engineered grains with higher levels of Beta-glucan
could help cereal companies produce breakfast cereals with
more heart health benefits. However, beer producers want
barley grain containing less Beta-glucan because that carbohydrate
clogs filters used in beermaking.
Physcomitrella patens, the moss in Liepman's study, has
just three CSL families, making it a great vehicle for
testing the effects of other genes. Genetically, it's
almost a blank slate.
"If we introduce a CSL from (another plant) into the moss
and notice that the moss now makes a different kind of
carbohydrate, then we've learned something very significant," Liepman
said. "We know how another carbohydrate is
made. Those who are interested in making energy crops or
improving the biomass in crop can use this information.
It can help them determine which gene to target or to
add."
Liepman's research is funded by a $400,000 USDA grant
that's split between his lab at EMU and collaborators at
the University of Rhode Island and Michigan Technological
University. A fourth researcher, at the University of Copenhagen
in Denmark, also collaborates on the project in an advisory
capacity.
"The folks in Rhode Island are really good at generating
transgenic moss," Liepman said. "They provide the moss
to us and we determine whether new CSL proteins are being
produced."
Michigan Tech conducts the carbohydrate analysis to determine
if there are differences in cell walls relative to regular
moss.
As more and more plant genomes have been sequenced, Liepman
says researchers have been able to work backward from what's
known to connect different CSL families with the production
of different carbohydrates in plants.
"Just 10-15 years ago , we knew nothing about these genes," Liepman
said. "Now, we've characterized dozens of them. That's
amazing progress. And, as we become better at it, the
pace is accelerating.'
