LAUSR

CRISPR/Cas9 system based on the adaptive immune system of bacteria is an emerging powerful technique of genome editing. Previously, we showed that transgenic rice transformed with a recombinant CRISPR/Cas9-OsJAZ9 binary plasmid display genetic chimerism in T0 generation, and the genetic chimerism includes homozygous and heterogeneous mutation of the target gene, OsJAZ9. The homozygous mutation of the T0 lines was stably transferred into the next generation, and all T1 plants of the T0 homozygous mutants were homozygous mutants. However, the fate of T1 plants with heterogeneous mutation remains poorly understood. In this study, we characterized target gene mutation in the progenies of the T0 lines with heterogeneous mutation to understand fate of the T0 lines with heterogeneous mutation. We found that some T0 lines such as lines 6 and 21 produce the T1 plants carrying homozygous mutation of OsJAZ9 through genetic segregation, while other T0 lines such as lines 3, 4 and 15 did not produce homozygous mutants in T1 generation unlike lines 6 and 21. These indicated that 40% of T0 lines with heterogeneous mutation produce the plants with homozygous mutation in T1 generation, suggesting that every T0 heterogeneous line does not produce the progenies with homozygous mutation through genetic segregation. However, because the portion of T0 lines with heterogeneous mutation (61%) is much bigger than that of T0 lines with homozygous mutation (8%) in T0 pool, these results propose that T0 heterogeneous mutants are useful to obtain CRISPR/Cas9-mediated homozygous mutants.