Ask a Plant Scientist: Principal Investigator Dr. Oliver Yu
Q: You’ve been at the Center now for 8 years. How are you feeling about the progress of your
lab’s work?
A: The Center has supported me well over the years and it’s certainly a very exciting
time to be here. All of our hard work is beginning to bear fruit as more institutions and
organizations now recognize the quality of our research. We have recently hired three
additional post-docs, nearly doubling the size of our team.
In the past six months we have received six different grants from a variety of sources,
including the Department of Energy (DOE), the National Science Foundation (NSF), the
U.S. Department of Agriculture, and the Missouri Soybean Association.
“WE BELIEVE
Q:
THAT DEPENDING
Your DOE grant and your more recent NSF grant are both related to biofuel production.
How are these two grants similar, and what differentiates them?
ON HOW CERTAIN
A:
ENZYMES
Both of these grants are primarily focused on metabolic engineering, which
is something the Center is gaining strength in. More specifi cally we are looking at
INTERACT, THE
enzyme interactions, and how these interactions help to control the fl ux of a pathway.
SAME STARTING
We believe that depending on how certain enzymes interact, the same starting
molecule can create multiple different compounds for the plant.
MOLECULE CAN
The DOE award focuses on lipid biosynthesis, basically studying how plants make oil.
CREATE MULTIPLE
This sort of fundamental research has the possibility of ultimately helping us engineer DIFFERENT
plants that concentrate more of their energy into the production of oil, which could then
COMPOUNDS FOR
be utilized as biodiesel energy.
THE PLANT.”
Our newest grant from the NSF is concerned with lignin biosynthesis. While this
grant also involves the development of biofuels, it is focused on the creation of easy-to-
breakdown biomass for ethanol production, as opposed to biodiesel.
Lignin is a chemical compound that makes up a large portion of a plant’s cell wall.
Roughly a quarter of the mass of dry wood is composed of lignins. We are looking
at lignin synthesis from the enzyme interaction point of view— this is the area less
traveled, less known, but I think it is very important.
Lignins do a few very important things for plants: they strengthen their stems, which
allow plants to grow tall and fend off diseases and insects. Lignins also reduce a plant’s
water loss by creating a hydrophobic barrier in the cell wall.
At the same time, lignin is a bad thing for ethanol production. Ethanol comes out of
the breakdown of cellulose, not out of lignin, at least for the moment. Companies that
make ethanol out of biomass are spending a great amount of energy and using toxic
chemicals to get rid of lignin because its presence in the cell wall prevents enzymes
from degrading the cellulose.
My research is examining how plants divert resources into lignin production. I want to
know why plants spend about 20 to 30 percent of their energy making lignin. How can
we redirect the resources into a different side of the pathway and how is this direction
controlled at the enzyme organization level?
There is a balance of what you can do to reduce lignin production without sacrifi cing
the normal growth and development of the plant. What amount of energy needs to be
directed to lignin production, and what can be directed elsewhere?
The same metabolic pathway that creates lignin also makes various fl avonoid
compounds, which play a variety of roles for the plant as well. Flavonoids are thought to
be a key factor in the many health benefi ts of soy. They are also essential to the plant’s
symbiotic process of nitrogen fi xation, which is a natural way that many legume species
fertilize soil. Clearly these pathways play multiple pivotal roles for plants like soy, and
furthering our understanding of them could lead to many different types of scientifi c
breakthroughs in the future. ■
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