10 Questions for a Quantitative Geneticist: Wellington Muchero


Wellington Muchero is a quantitative geneticist at the Bioenergy Science Center in Oak Ridge, Tennessee. Photo by Jason Richards, Oak Ridge National LaboratoryWellington Muchero is a quantitative geneticist at the Bioenergy Science Center in Oak Ridge, Tennessee. Photo by Jason Richards, Oak Ridge National Laboratory (hi-res image)

Since 2007, the Energy Department’s three BioEnergy Research Centers have pursued breakthroughs in biofuel technologiesworking to move these discoveries toward commercialization. Meet Wellington Mucheroa quantitative geneticist at the BioEnergy Science Center in Oak Ridge, Tennessee.

This article was first posted on the blog.

Question: What led you to a career in science?

Wellington Muchero: I took the scenic route to end up in science. All through my school years, mastering scientific principles and designing or predicting outcomes from experiments seemed to come naturally. However, I somehow ended up working as a life insurance administrator. It took three years of office drudgery for me to realize that science was where I really wanted to be. As soon as I got a part-time job in a plant molecular biology lab as a college student, I realized there was no turning back.

Q: Do you have advice for students interested in science careers?

WM: I believe science was founded on curiosity and contemplating alternatives to doctrine. So I would encourage students to stay curious and be defiant in their critical thinking. Without the latter, we would still believe that the earth was flat and the sun revolved around us.

Q: What is 'cell wall recalcitrance' and why does it matter for biofuels production?

WM: Cellulose is one of the most abundant polymers on earth -- most of which occurs as a structural component of plant cell walls. Since cellulose is made up of repeating units of glucose sugars we can use a variety of approaches to break down cellulose fiber into simple sugars that can be fermented to produce ethanol fuel.

However, in cell walls, cellulose is protected by the polymer, lignin, which is very resistant (recalcitrant) to degradation such that enzymes cannot access the target cellulose fibers. To overcome this barrier, biomass undergoes costly pretreatment to remove lignin and expose sufficient cellulose fibers for fermentation. This added cost of production translates into higher costs of ethanol-based fuels at the pump.

Q: At the BioEnergy Science Center, you are a quantitative geneticist. How do genetics help the bioenergy field?

WM: Broadly, genetics allows us to understand how variations at the molecular level (DNA) result in the expression of favorable or unfavorable plant traits. In the bioenergy field, there are significant genetically-driven differences among plant genotypes (varieties) in cell wall recalcitrance. We have reproducibly demonstrated that there can be up to two-fold differences in lignin content, and up to three-fold differences in ethanol yield from Populus trees grown under the same conditions. This gives us tremendous opportunity to identify specific genetic mutations that result in reduced lignin content, or in types of lignin that are easier to breakdown. With that knowledge, we can identify naturally occurring superior varieties or we can design plants with lower or ‘softer’ lignin content for use as feedstock in ethanol production.

Q: Can you share a bit about one of your current projects?

WM: Through experiments we conducted in three field sites in Oregon and California, we identified naturally occurring genetic mutations that appear to result in the lowest lignin content we have recorded so far after analyzing more than 1,000 Populus trees. We have been working to isolate the specific version of those genes in laboratory experiments.

Q: Why are the BioEnergy Research Centers important?

WM: The diversity and breadth of expertise that Bioenergy Research Centers bring to bear on the challenges of enhancing biofuels production is unmatched. Within our own BioEnergy Science Center, we have expert plant biologists, computer scientists, chemical engineers, process engineers, microbiologists, analytical chemists, technology transfer specialists and industrialists -- all under one umbrella organization.

Concurrently, we have scientists working to find the best plant feedstock, the best cell wall deconstruction platform, the best microbe, the least expensive pretreatment option, the best way to computationally use large datasets to iteratively go through the same process and finally we have people ready to commercialize these technologies for industrial-scale ethanol production. I cannot imagine how frustrating it would be to try all this with discrete, standalone institutions. By bringing together all these fields and their associated facilities, BRCs enable collaboration, rapid and seamless transfer of materials and ideas for experimental validation.

Q: What research are you watching (beside your own)?

WM: The Mars Exploration Rovers. The prospect of life on another planet is a fascinating one for me. Also, a good part of my job is figuring out how genes respond to different environments and then predicting the best combination of genes for a particular environment. In my moments of unrestrained imagination, I keep thinking if I can engineer a plant to grow on Mars and help that seemingly barren landscape look better, I could retire a happy scientist.

Q: What do you enjoy doing in your free time?

WM: I enjoy indulging my daughter, Tatenda, with her favorite activities. She is 4 1/2 with time for almost everything in the world. If I have any time left, I enjoy trail biking -- East Tennessee has some of the most scenic trails.

Q: What is your favorite tool in the lab?

WM: The -80 degrees C (-112 degrees F) freezer. It’s the repository of my most important materials as well as my wildest dreams (in the form of DNA samples I hope to look at some day). It’s also an enabling tool for my procrastinating self. Once I have samples in there, I can relax knowing they won’t go bad for a long time. That is, if my colleague Lee Gunter doesn’t go on a de-cluttering binge and decide to toss out anything that looks forgotten.

Q: Last question -- what is on your reading list right now?

WM: Again, my daughter rules this part of my life. I have been reading anything that has a princess or SpongeBob on the cover. Outside of that I usually manage to sneak in some of my own so I have been reading “Veinte Poemas de Amor y una Canción Desesperada” by Pablo Neruda and also “The Book of Not: A Sequel to Nervous Conditions” by Tsitsi Dangarembga.

 -  Morgan McCorkle,  865.574.7308,  July 01, 2013

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