Wesley, T. | bioRxiv Science

bioRxiv2025

Population and adaptation history of 739 Thlaspi arvense natural accessions

Pennycress (Thlaspi arvense) is a promising intermediate oilseed crop, producing oil suitable for conversion to biofuels--including aviation fuels. While domestication efforts are ongoing, a deeper understanding of the genetic architecture of traits is crucial for informing future breeding efforts. Here, we conducted the largest genomic and phenotypic survey of pennycress to date, analyzing 739 accessions collected across four continents. Leveraging whole-genome sequencing and field-collected phenotypes, we characterized the standing genetic variation underlying key agronomic traits and climate resilience. Our findings revealed multiple independent migration events to North America, with substantial genetic admixture. We identified homologs of Arabidopsis thaliana flowering-time genes that contribute to adaptation and demonstrated the agronomic benefits of winter-type pennycress. Furthermore, through multi-season field trials, we identified a genomic region containing a cluster of mTERF genes strongly associated with green canopy coverage, a critical trait for biomass retention and yield stability. These insights provide a genomic roadmap for accelerating pennycress domestication and improving its resilience to climate variability.

genomics↗

bioRxiv2025

Loss of PIF7 attenuates shade and elevated temperature responses throughout the lifecycle in Pennycress

Pennycress (Thlaspi arvense) is being developed as a winter annual intermediate oilseed bioenergy crop in the Midwest during typical fallow periods. Crucial work remains to domesticate and optimize pennycress for incorporation into cropping systems and increasing resilience to rising temperatures. We found that increased planting density reduces biomass and hastens time to flowering and maturity, which are associated with shade avoidance responses. In controlled conditions, we found that pennycress elongates in response to foliar shade and increased ambient temperatures (28 {degrees}C). We applied the knowledge base from Arabidopsis thaliana to manipulate genes in the PHYB signaling pathway to simultaneously decrease the shade avoidance response during interseeding and tissue responses to elevated temperatures. Evaluation of CRISPR alleles of PIF7 shows that pif7 reduces organ elongation to competition and heat cues and retains a compact rosette when exposed to shade or elevated temperature and their combination. Crucially, yield and oil content were unaltered in pif7 and plants maintained earlier flowering in stress conditions. Furthermore, indicators of plant health, such as hue, chlorophyll indices, and root system architecture, were improved between wild type and pif7. This is evidence that plant architecture and physiological health can be uncoupled under competition and heat conditions, supporting our efforts to attenuate morphological responses to environmental cues. We propose this strategy for reducing SAR, improving pennycress performance at high densities, for during interseeding establishment in standing crops, and in a warming climate.

plant biology↗