Rapid improvement of grain weight via highly efficient CRISPR/Cas9-mediated multiplex genome editing in rice

Journal Article / 2016

Xu, Rongfang; Yang, Yachun; Qin, Ruiying; Li, Hao; Qiu, Chunhong; Li, Li; Wei, Pengcheng; Yang, Jianbo

Most of the important agronomic traits in crop plants, such as yield, quality and stress response, are quantitative and jointly controlled by many genomic loci or major genes. Improving these complex traits depends on the combination of beneficial alleles at the quantitative trait loci (QTLs). However, the conventional cross breeding method is extremely time-consuming and laborious for pyramiding multiple QTLs. In certain cases, this approach might be technically difficult because of close linkage between genes separately responsible for desirable and undesirable traits. Newly developed sequence-specific nuclease (SSN) technology provides a practical method to manipulate multiple genomic targets. For example, a rice triple mutant of BADH2 (Betaine Aldehyde Dehydrogenase 2), CKX2 (Cytokinin Oxidase 2) and DEP1 (Dense and Erect Panicle 1) has been generated using the transcription activatorlike effector nuclease (TALEN) method ( Shan et al., 2015). Another SSN tool, the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, has a simpler structure and a more convenient construction procedure that might be even more suitable to simultaneously edit multiple targets. In plants, several CRISPR/Cas9 multiplex editing tools have been reported (Xing et al., 2014; Ma et al., 2015; Wang et al., 2015; Xie et al., 2015; Zhang et al., 2015). Although these tools have different efficiencies, all of them generated simultaneous targeted mutations in multiple genes, suggesting that it might be possible to improve crop quantitative traits by taking advantage of a CRISPR/Cas9-mediated multiplex genome editing system.