Using CRISPR-Cas9 to create knockout mutants in insects

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (CRISPR/Cas9) is a potent genome editing tool that has rapidly revolutionized research in natural science disciplines. The CRISPR/Cas9 system surpasses traditional zinc finger nucleases and transcription activator-like effector nucleases because of its simplicity in design, cost-effectiveness, and labor intensity. The CRISPR/Cas9-mediated genome editing system has been used to generate precise and targeted mutations in many different organisms, including insects. However, there is still a lack of a comprehensive review that systematically summarizes the successful utilization of the CRISPR/Cas9 system in generating knockout (KO) mutations in insects (both model and non-model). Thus, this review provides a comprehensive analysis of the current advancements in CRISPR/Cas9-based KO mutants in insects, including both model and non-model species. We also discussed the limitations of the CRISPR/Cas9 system. Finally, we discuss the biosafety concerns associated with the release of CRISPR/Cas9-edited insects into the environment and draw inroads and insights into the future application of the CRISPR/Cas9 system in insects.