摘要
Dear Editor The recent development of sequence-specific nuclease systems, i.e., TALENs and CRISPR/Casg, has made genomic targeting easier in many organisms including plants （Li et al., 2012; Cong et al., 2013; Joung and Sander, 2013; Li, et al., 2013; Shan et al., 2013; Liang et al., 2014; Zhang et al., 2014）. Mutations induced by CRISPR/Cas9 usually occur around the cleavage sites at three bases upstream of the protospacer-adjacent motif （PAM）, producing insertion and deletion of nucleotides. For diploid organ- isms, such targeted mutations may happen in one or both homol- ogous chromosomes. Previous reports showed that CRISPR/ Cas9-based genomic editing in some plants mainly produced complicated mosaic （chimeric） mutations in the somatic cells of the first generation transgenic plants （Li et al., 2013; Mao et al.,
Dear Editor The recent development of sequence-specific nuclease systems, i.e., TALENs and CRISPR/Casg, has made genomic targeting easier in many organisms including plants （Li et al., 2012; Cong et al., 2013; Joung and Sander, 2013; Li, et al., 2013; Shan et al., 2013; Liang et al., 2014; Zhang et al., 2014）. Mutations induced by CRISPR/Cas9 usually occur around the cleavage sites at three bases upstream of the protospacer-adjacent motif （PAM）, producing insertion and deletion of nucleotides. For diploid organ- isms, such targeted mutations may happen in one or both homol- ogous chromosomes. Previous reports showed that CRISPR/ Cas9-based genomic editing in some plants mainly produced complicated mosaic （chimeric） mutations in the somatic cells of the first generation transgenic plants （Li et al., 2013; Mao et al.,
