Phippen, W. | bioRxiv Science

bioRxiv2025

Pennycress (Thlaspi arvense L.) Seed Persistence in the Field After Two Years

Field pennycress (Thlaspi arvense L.), is a new oilseed winter annual crop being investigated as a source of biofuel in the United States. The purpose of this study is to assess long term survivability and dormancy of both wild-type pennycress and gene-edited golden pennycress seed. Seeds from one wild type and three gene-edited golden types that carried an edit to TT8 gene were buried at 2 cm and 15 cm depths under well-drained and poorly-drained field conditions. The seeds were exhumed at 2, 4, 6, 12, 18, and 24 months after burial and germinated to determine the viability of the seed over time. All golden seeded gene-edited lines decreased to 0% germination by 6 months while the wild black seeded variety ARV1 retained almost 60% germination after 2 years. A significant difference was seen in the ARV1 survival in the well- drained field but not in the poorly-drained field. However, there was no significant difference in seed viability for burial depth in the well-drained field but there was significant difference for burial depth in the poorly-drained field. These results indicate that gold seeded varieties carrying the edit to TT8 through gene-editing have dramatically decreased the survivability of the seed in the seedbank. Reduced survivability will greatly assist in the adoption of golden pennycress as a new viable off-season crop in the Midwest without concerns of adding to the seedbank or serving as weed pressure in primary crops.

genetics↗

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↗