Genome editing opens a new era of genetic improvement in polyploid crops

Sequence-specific nucleases(SSN) that generate double-stranded DNA breaks(DSBs) in genes of interest are the key to site-specific genome editing in plants. Genome editing has developed into one method of reducing undesirable traits in crops by the induction of knockout mutations. Different SSN-mediated genome-editing systems, including LAGLIDADG homing endonucleases or meganucleases, zinc-finger nucleases, transcription activator-like effector nucleases and clustered regularly interspaced short palindromic repeats, are emerging as robust tools for introducing functional mutations in polyploid crops including citrus, wheat, cotton, soybean, rapeseed, potato, grapes, Camelina sativa,dandelion, and tobacco. The approach utilizes knowledge of biological mechanisms for targeted induction of DSBs and their error-prone repair, allowing highly specific changes at designated genome loci. In this review, we briefly describe genome-editing technologies and their application to genetic improvement of polyploid crops.