Genome Editing in Plants for Precision Breeding: Yesterday, Today, and Tomorrow

Genome editing has revolutionized many processes, including crop improvement and production of next-generation hybrid seeds from genic male sterile lines and maintainers. Different genome editing techniques include zinc-finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas), and came into existence after the success of engineered meganucleases. Insertion of DSBs at specific sites and induction of the repair process to bring about desirable amendments in gene functions are the prime tasks of genome editing approaches. CRISPR/Cas system, developed recently, relies on CRISPR-RNAs for recognizing the targeted sequence and is far more effective than the previously developed genome editing approaches. The refinement of abiotic and biotic stress tolerance, enhancement of quality traits, and improvement of yield represent the changes that have been achieved through various genome editing practices. This update review presents an overview of genome editing in plants and the currently available genome-editing tools to evaluate their effectiveness, along with their positive and negative aspects.