Genome editing of oilseed species by CRISPR/Cas9 for trait improvement

Abstract

The demand for vegetable oils for food and other applications is rapidly increasing due to a growing population and an urgent need to replace fossil oils. Furthermore, there are several challenges facing agricultural production, such as a shortage of arable land, climate change, and water pollution due to nutrient leaching from extensive use of fertilizers and tillage. More sustainable agricultural systems, better use of side-streams, domestication of novel oil crops, and improvement of existing oil crops are important for global food security and the supply of raw materials for different industries. In Sweden, rapeseed is the main oil crop, but is mainly cultivated in the southern region of Sweden due to its weak cold tolerance. The seed cake is rich in protein, but is underutilized due to high levels of anti-nutritional compounds such as glucosinolates. Field cress (Lepidium campestre) is a novel cold-hardy and high-yielding oilseed crop that can be undersown with a spring cereal in cool climates as a cover crop for reducing nutrient leaching and soil erosion, while producing a valuable seed oil and improving the cereal yield. Development of the CRISPR/Cas9 genome editing system has revolutionized the field of biology and led to major advances in plant science. This novel breeding tool offers great opportunities for accelerated trait improvement of crops with high precision. In this thesis, we have developed efficient protocols for protoplast transfection and regeneration of field cress and rapeseed, and demonstrated their usefulness in genome editing via CRISPR/Cas9 by mutating multiple glucosinolate transporter genes in rapeseed and field cress for reducing seed glucosinolate contents, and by mutating key genes for improving the oil quality of field cress.