Recently, researchers led by Professor Kejian Wang at China National Rice Research Institute (CNRRI) of Chinese Academy of Agricultural Sciences (CAAS) reported the SpCas9 variant xCas9 with a broad PAM compatibility in rice. This study has been published online in Plant Biotechnology Journal. It is revealed that xCas9 variants have the potential to become versatile tools which will expand the scope of genome editing in rice.

The common Streptococcus pyogenes Cas9 (SpCas9) recognizes canonical NGG PAM, which restricts the editable range of the rice genome. Although several tools have been developed for genome editing, versatile nucleases recognising various PAMs are still largely required to expand the genome editing toolbox. By modifying rice codon-optimised SpCas9 to generate xCas9, researchers found that xCas9 can be used for genome editing at GAA, AGA, TGT, CGC, GGG, NGG and CAG PAMs in rice. The relatively low efficiency of xCas9 in rice illustrates the need for more in-depth work on ways to improve the working efficiency of xCas9 in plants.

This work was supported by the National Key Research and Development Program of China (Grant: 2016YFD0101800) and the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences. The research finding has been published in Plant Biotechnology Journal online on December 13, 2018 (DOI: 10.1111/pbi.13053). More details are available on the link below: https://onlinelibrary.wiley.com/doi/full/10.1111/pbi.13053