The oilseed species Thlaspi arvense (pennycress)-a weed that was only recently removed from the wild-has the potential to provide new sources of food and bioproducts when grown as a winter cover crop. Domestication of wild species has historically taken hundreds to thousands of years, but by making use of large-scale high-throughput comparative gene and phenotype analyses, along with recently developed technological tools, it has been possible to greatly accelerate this process. By taking advantage of extensive gene and phenotype knowledge in the related plant Arabidopsis, mutations for early maturity, reduced pod shatter, reduced seed glucosinolates and improved fatty acid composition were identified. Progress has been made to rapidly stack these traits in order to domesticate the plant, allowing it to fit within current crop cycles and to have improved seed harvestability and nutritional content. Pennycress, domesticated as a winter cover crop, may provide new sources of food, animal feed and bioproducts-and solutions to food security.

Thlaspi arvense (pennycress) has the potential for domestication as a new oilseed crop. Information from an extensive body of research on the related plant species Arabidopsis can be used to greatly speed this process. Genome-scale comparisons in this paper documented that pennycress and Arabidopsis share similar gene duplication. This finding led to the hypothesis that it should be possible to isolate Arabidopsis-like mutants in pennycress. This proved to be true, as forward genetic screens identified floral and vegetative pennycress mutants that were similar to mutants found in Arabidopsis. Extending this approach, it was shown that most of the pennycress genes responsible for the formation of oxidized tannins could be rapidly identified. The causative mutations in the pennycress mutants could be identified either by PCR amplification of candidate genes or through whole-genome sequencing (WGS) analysis. In all, WGS was used to characterize 95 ethyl methane sulfonate mutants, which revealed a mutation rate of 4.09 mutations per megabase. A sufficient number of non-synonymous mutations were identified to create a mutant gene index that could be used for reverse genetic approaches to identify pennycress mutants of interest. As proof of concept, a Ta-max3-like dwarf mutant and Ta-kcs5/cer60-like wax mutants deficient in the biosynthesis of long chain fatty acids were identified. Overall, these studies demonstrate that translational genomics can be used to promote the domestication of pennycress. Furthermore, the ease with which important findings could be made in pennycress makes this species a new potential model plant.

Field pennycress ( Thlaspi arvense L.) is currently being developed as a new cold‐tolerant oilseed crop. In natural populations, pennycress, like many Brassicaceae relatives, can exhibit either a winter or spring annual phenotype. Pennycress is a diploid relative of Arabidopsis thaliana, a model species that has been used to study many adaptive phenotypes, including flowering time and developmental timing. In Arabidopsis and other Brassicaceae species, mutations in negative regulators of flowering, including FLOWERING LOCUS C and FRIGIDA can cause the transition to a spring annual habit. The genetics underlying the difference between spring and winter annual pennycress lines are currently unknown. Here, we report the identification of four natural alleles of FLC in pennycress that confer a spring annual growth habit identified through whole genome sequencing, cosegregation analyses, and comparative genomics. The global distribution of these spring annual alleles of FLC suggests that the spring annual growth habit has arisen on several independent occasions. The two spring annual FLC alleles present in European accessions were only identified in North American accessions collected in southern Montana, which indicates accessions harboring these two alleles were introduced to North America, likely after pennycress became a widespread species on the continent. These findings provide new information on the natural history of the introduction and spread of spring annual pennycress accessions from Europe into North America. At the molecular level, these findings are important for the ongoing development of pennycress as a winter annual crop. An enhanced understanding of the regulation of flowering in this species should allow for the fine‐tuning of flowering in commercial varieties.

AbstractThe oilseed speciesThlaspi arvense(pennycress) is being domesticated as a new crop that can provide both important ecosystem services and intensify farmland output. Through the use of high throughput sequencing and phenotyping, along with classical mutagenesis key traits needed for pennycress domestication have been identified. Domestication traits identified herein include reduced pod shatter, early maturity, reduced seed glucosinolate levels, and improved oil fatty acid content. By taking advantage of pennycress’ close genetic relationship withArabidopsis thaliana, the causative mutations responsible for each of these traits have been identified. These mutations have been used to develop molecular markers to begin to stack the traits into individual lines.