Creating a new oilseed crop, pennycress, by combining key domestication traits using CRISPR genome editing

Considerable off-season farmland lies fallow because few crops can profitably fit between primary crops. As a remedy, we performed de novo domestication of the freeze-tolerant, rapid-cycling wild brassica Thlaspi arvense L. (field pennycress), identifying and stacking CRISPR-Cas9-induced mutations that have minimal impacts on seed yields. High-yielding varieties were created with seed compositions such as 'double-low' canola (low erucic acid and reduced glucosinolate) and reduced seed fibre content. Seed glucosinolate content was reduced by 75% by combining mutations in R2R3-MYB (MYB28/HAG1) and basic helix-loop-helix MYC (MYC3) transcription factors. Pennycress weediness was greatly reduced by knockout of the basic helix-loop-helix transcription factor TRANSPARENT TESTA8 (TT8), which lowered seed dormancy and seed coat protections, thereby mitigating re-emergence in fields. Domesticated pennycress offers farmers a low-carbon-intensity intermediate crop that fits between two full-season summer crops, resulting in three cash crops in 2 years, conferring cover-crop-like ecosystem benefits while producing grain for renewable fuels and enhanced food security.