Postdoctoral Associate Donald Danforth Plant Science Center Olivette, Missouri
Body of Abstract: Pennycress (Thlaspi arvense), an emergent winter annual bioenergy oilseed cover crop, is under development to be grown in the Midwest during typical fallow periods. Pennycress varieties can yield over 1680 kg ha-1 (1500 lb ac-1) of seeds producing 600 liters ha-1 (65 gal ac-1) of oil annually without competing with food crops. However, crucial work remains to domesticate and optimize pennycress for incorporation into present cropping systems and its resilience to climate change. For example, interseeding into standing fields in late fall leads to shade-induced responses in pennycress. Similarly, higher temperatures during planting can also cause seedlings to elongate, resulting in poor stand establishment. We have established that pennycress is shade and heat intolerant and elongates in response to these stresses. Excessive elongation creates a cyclical dilemma, in which the elongated plants increasingly shade their neighbors, further inducing retaliatory elongation responses in efforts to outgrow neighboring plants. These morphogenic changes are undesirable in cropping systems as elongated plants establish poorly, are more prone to lodging, and typically reduce yield. We are using the knowledge base from Arabidopsis thaliana to manipulate genes in the PHYB signaling pathway to simultaneously improve resilience to shade present during interseeding and increasing winter and spring temperatures. Evaluation of CRISPR and EMS alleles of PIF7 show that pif7 has reduced organ elongation and retains a compact rosette when exposed to shade, elevated temperature, and combined stresses while maintaining yield and desirable phenotypes such as earlier flowering in stress conditions. By lowering elongation responses to shade and elevated temperature, we aim to increase pennycress ground cover when grown at high densities, reduce shade-induced responses when interseeded into standing crops, and elongation in response to higher temperatures. Future work will determine if these changes to shade and temperature responses improve pennycress’s performance and productivity in the field.