Graduation Term

Fall 2025

Degree Name

Master of Science (MS)

Department

School of Biological Sciences

Committee Chair

John Sedbrook

Committee Member

Tom Hammond

Committee Member

Victor Kirik

Abstract

Pennycress (Thlaspi arvense L.) was once regarded as a common weed but is now being domesticated as a multifunctional crop. Its winter annual growth habit makes it a promising intermediate cover crop that can be planted on fallow land, while its high seed oil content and protein-rich seed meal provide potential for biofuel and feed applications. However, persistent weedy traits such as seed dormancy and elevated glucosinolate levels continue to hinder commercialization of pennycress.

Building on findings from Arabidopsis thaliana (Arabidopsis), this study targeted SOMNUS (SOM) and bZIP67, key regulators of seed dormancy, and UMAMIT29 and UMAMIT30, glucosinolate transporters, for CRISPR–Cas9 mutagenesis in pennycress. Single and double knockout mutants targeting seed dormancy were generated in the ARV1 winter-type background and double knockout mutants targeting glucosinolates were generated in the Spring 32-10 background. Generated som and zip single mutants and som zip double mutant lines in ARV1 along with previously generated single and double mutant lines in the Spring32-10, tt8 (Spring 32-10), and tt8 (ARV1) were subjected to different germination assays that relate to light-mediated and abscisic acid (ABA) signaling pathways to evaluate dormancy and germination responses.

Although no single mutant consistently enhanced germination across all backgrounds, the results revealed clear background-dependent effects on seed germination behavior. These findings suggest that the genetic background strongly influences the functional outcomes of knockouts in dormancy-related genes and highlight the divergence between regulatory-dormancy pathways in Arabidopsis and pennycress. This work expands our understanding of the molecular regulation of seed germination in pennycress and contributes to ongoing efforts to improve its domestication as a sustainable winter cover and oilseed crop.

Access Type

Thesis-Open Access

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Available for download on Sunday, January 30, 2028

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