The Science
Oils produced from nonfood crops can be converted into biofuels that can reduce the need for fossil fuels. In oilseed crops like canola, yellow-seeded varieties generally produce more oil than their brown-seeded counterparts. Camelina is a bioenergy crop and a close relative of canola. Traditional camelina seeds are brown. Using the tools of modern genetics, scientists disrupted genes called TT8 that are responsible for making brown seed color. Those genes also play a key role in oil production. The new engineered camelina produces light yellow seeds and accumulates more than 20% more oil than ordinary varieties.
The Impact
Oil produced by nonfood crops like camelina can be made into transportation fuels. These plants use sunlight to power the conversion of atmospheric carbon dioxide into seed oil. This research demonstrates the potential of creating new varieties in camelina using modern biotechnology. Understanding the regulation of lipid metabolism by TT8 and other oil-producing factors may provide additional gene targets that can be manipulated to increase oil yields. The use of new varieties with increased oil content may increase the yield of feedstocks for biofuels and other bioproducts. Such efforts can contribute toward a net-zero carbon bioeconomy.
Summary
Breeders of oilseed crops like canola select yellow-colored varieties because they produce more oils than their brown-seeded counterparts. Camelina is a close relative to canola, but the plant has no naturally occurring yellow-seeded varieties. Scientists have discovered genes for making seed colors in many oilseed plants. This research identified three genes called TT8 in camelina and simultaneously disrupted them using modern CRISPR gene editing technologies. TT8 is responsible for making pigments in seed coat. The gene also plays a key role in oil synthesis in seeds. Disrupting TT8 effectively stopped the pigment synthesis, meaning that the plant committed more carbon to making oil instead. Many genes involved in oil synthesis and the production of fatty acids, the building blocks of oil, were expressed at increased levels in seeds from the CRISPR-edited plants.
The result was a dramatic increase in oil accumulation. The seed of the light yellow-seeded camelina accumulates more than 20% more oil than the natural brown-seeded varieties. The engineered seeds contained another positive surprise: the levels of proteins and starch were not altered. The seeds germinated normally and the targeted gene mutations were stably carried to subsequent generations.
Funding
This research was supported by the DOE Office of Science through a project known as “ECON: Enhancing Camelina Oilseed Production with Minimal Nitrogen Fertilization in Sustainable Cropping Systems” led by Montana State University. Additional funding was provided by the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), a DOE-funded Bioenergy Research Center led by the University of Illinois Urbana-Champaign.
