CRISPR/Cas9 has emerged as a promising allowing precise genomic manipulation in rice and other crops. However, due to the prevalence of non-homologous end joining (NHEJ) over homology directed repair (HDR) in the repair of CRISPR/Cas9-induced double strand breaks (DSB), this genome editing tool has been mostly used to generate random insertions and deletions (Indels) in plants, target gene knock in (KI) or replacement is still far from common practice. Compared to mammalian and human cells, one of the obstacles for HDR in plants is the efficient delivery of repair donors into the cells.
Recently, geminiviruses have been used for HDR in plants, principally because their DNA genomes could serve as repair templates, and they replicate to high copy number. The research group from Prof. ZHU Jiankang’s lab at Shanghai Center for Plant Stress Biology (PSC), Shanghai Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Science (CAS), develops a simple and efficient approach for KI in rice based on the geminivirus WDV (wheat dwarf virus). By combining CRISPR/Cas9 to produce double strand breaks and WDV-derived vectors to deliver abundant donor DNA into rice cells, targeted KI frequency can reach up to 19.4% in transgenic rice plants, advocating its considerable application for rice research and breeding.
The work, entitled “Gene targeting by homology-directed repair in rice using a geminivirus-based CRISPR/Cas9 system”, has been published online in Molecular Plant on March 18, 2017.
This work is supported by the Chinese Academy of Sciences.