Dear Editor,Genome editing technologies enable precise modifications of DNA sequences in vivo and offer great promise for crop improvement.CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated Cas9) has revolutionized genome editing because of its simplicity and versatility (Cong et al.,2013).However,the majority of the editing events reported in plants were through error-prone non-homologous end joining (NHEJ) to generate mutations and gene knockouts (Miao et al.,2013;Voytas and Gao,2014;Xie et al.,2014;Ma et al.,2015).While complete knockouts and loss-of-function mutations are very valuable in defining gene functions,their applications in crop improvement are somewhat limited because many agriculturally important traits are conferred by point mutations or change of gene expression levels.