The clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein9 (Cas9) genome editing system
(CRISPR/Cas9) is adapted from the prokaryotic type II adaptive immunity system. Recently, CRISPR/Cas9 technology has
emerged as a powerful approach for targeted genome modification in eukaryotic organisms from yeast to human cell lines. The
CRISPR/Cas9 tool surpasses other programmable nucleases, such as ZFNs and TALENs, for its simplicity and high efficiency. Its
successful application in several plant species promises enormous potential for basic and applied plant research. These tools have
been efficiently used for trait discovery and for the generation of plants with high crop yields and resistance to biotic and abiotic
stresses. Various plant-specific CRISPR/Cas9 vector systems have been established for adaption of this technology to many plant
species. Due to complex genomic architecture, it is challenging to edit all of the genes/genomes using a particular genome editing
tool. In addition, we provide a perspective on the challenges of CRISPR/Cas9 technology and its importance for basic plant
research and crop genetic improvement. Therefore, to overcome this challenging task, CRISPR/Cas9 genome editing tools have
been developed to facilitate efficient genome editing.