revealed that several regenerated plants carried several types of
mutated alleles but no wild type allele (G1#11A and G1#15A;
Table 1), suggesting that mutations were induced frequently during
cell proliferation in a cell line. In addition, only a single type of allele
was identified in G3#48A, suggesting that the mutagenesis can
occur in both alleles at an early developmental stage, presumably
just after a T-DNA integration event. On the other hand, genotype
analysis of T1 plants identified only those alleles that were found to
be present in plantlets just after regeneration (Tables 1 and 2),
implying that mutagenesis might occur only rarely after differentiation.
Similarly, the CRISPR/Cas9 systemwas reported to be highly
efficient at an early stage of cell division in rice [25].