Application of DNA-free CRISPR/Cas-mediated Genome Editing in Crops: A Review

Clustered regularly interspaced short palindromic repeats/CRISPR associated nuclease 9 (CRISPR-Cas9) system was instigated first into eukaryotes in the last ten years are becoming productive and worldwide application for genome modification. Genome engineering through insertion of foreign DNA insert have numerous disadvantages which could be overcome by use of DNA-free genome editing. Various ways of DNA-free genome editing mediated by CRISPR/Cas systems are CRISPR/Cas delivery as ribonucleoprotein, delivery of CRISPR/Cas as virus-like particles and agrobacterium-based delivery of CRISPR/Cas. Crop improvement through DNA-free genome editing via CRISPR/Cas have been applied in rice, wheat, maize, tomato, soybean and rare species like Nicotiana benthamiana etc. It is method of choice for precise genome editing without genome shuffle in an organism.