Comparing Genetic Characteristics of Retrotransposon TOS17 During Different Tissue Culture Processes in the Rice Cultivars Nipponbare and Shishoubaimao

As a retrotransposon, TOS17 was a useful tool for rice genetic and functional genomic research. To ascertain the feasibility of constructing a TOS17 insertion mutation library in the rice cultivar Shishoubaimao, the genetic and expression characteristics of TOS17 were analyzed. We made solid and suspension tissue cultures and confirmed the copy numbers of TOS17 at different time points in both tissue culture processes by real-time quantitative PCR (RT-qPCR). Three primary copies of TOS17 were detected in naturally grown Shishoubaimao. TOS17 was activated by tissue culture, and the copy numbers of TOS17 increased along with a prolonged tissue culture time in both the Nipponbare and the Shishoubaimao cultivars. Therefore, Shishoubaimao is a potential candidate for constructing a TOS17 insertion mutant library. Compared with Nipponbare, TOS17 was more active in Shishoubaimao during tissue culture. Higher copy numbers of TOS17 were obtained with the suspension tissue culture process than with the solid tissue culture process over the same time courses. We concluded that 3–4 months of suspension tissue culture time is suitable for constructing a TOS17 insertion mutant library in Shishoubaimao.