Application of CRISPR/Cas9 in Rapeseed for Gene Function Research and Genetic Improvement

Brassica napus L. provides high-quality edible oil and clean energy for humans. For a long time, rapeseed breeders have tried to breed improved varieties through traditional breeding strategies. However, B. napus is an allotetraploid species containing many repetitive sequences. It is very inefficient to change traits through traditional genetic methods such as hybridization and random mutagenesis due to gene redundancy. Today, the burgeoning CRISPR/Cas9 technology has been applied in polyploid rapeseed for gene function research and targeted genetic improvement because of its unique advantages of high efficiency and simplicity. This review summarizes current reports about the application of CRISPR/Cas9 system for gene function research and genetic improvement in rapeseed, involving important agronomic traits such as yield, oil content, and fatty acid composition. The application status of emerging precise genome editing technology in plants and several potential limitations and technical bottlenecks in rapeseed gene editing is discussed, which will provide confidence for researchers in rapeseed gene function research and genetic improvement through genome editing technology.