Graduation Term

Summer 2025

Degree Name

Doctor of Philosophy (PhD)

Department

School of Biological Sciences

Committee Chair

John Sedbrook

Committee Member

Nathan Mortimer

Committee Member

Nicholas Heller

Committee Member

Tom Hammond

Committee Member

Viktor Kirik

Abstract

Pennycress (Thlaspi arvense L., field pennycress) is a winter annual oilseed plant which we are domesticating for the U.S. Midwest Corn Belt and other temperate regions. Pennycress confers cover crop benefits as an offseason crop and is unique in having extreme cold tolerance, high oilseed yields, and a relatively short life cycle. In the southern U.S. Midwest, pennycress can fit between corn and soybeans resulting in three crops in two years. We have partnered with the startup company, CoverCress, Inc., which has commercialized varieties we co-developed that produce seeds low in erucic acid content and indigestible fiber and which are not weedy. To improve domesticated pennycress further, I employed CRISPR genome editing to introduce dozens of mutations into genes we hypothesized could improve agronomic traits including reduced seed glucosinolate content, increased seed size, and enhanced drought tolerance. After generating a large number of mutant combinations, I identified novel mutant combinations that reduced seed glucosinolate content to within FDA-approved limits, resulting in a pennycress variety having canola-like seed composition with no negative yield impacts. I also meaningfully increased seed size without negative growth effects, identifying unexpected differences in seed oil and protein content which may be due to differences in intracellular lipids packaging. Finally, our morpho-physiological, transcriptomic, and metabolomic studies of pennycress drought responsiveness revealed pennycress naturally is drought resilient and likely has unique molecular mechanisms for dealing with drought stress. Together, my dissertation research has advanced the domestication of pennycress and understandings of the molecular underpinnings, helping pave the way for its planting on millions of acres in the U.S. Midwest.

Access Type

Dissertation-Open Access

DOI

https://doi.org/10.30707/ETD.1763755358.561343

Available for download on Friday, September 10, 2027

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