Contribution of the Tos17 retrotransposon to rice functional genomics

The ongoing international efforts of the Rice Genomic Sequencing Project ha ve already generated a large amount of sequence data. The next important ch allenge will be to construct saturation mutant lines for the functional ana lysis of all of the genes revealed by this effort in the context of the ric e plant as a whole. Recently, the endogenous retrotransposon Tos17 has been shown to be an efficient insertional mutagen. Considering the ease of muta genesis with Tos17 and its multiple-copy nature, saturation mutagenesis wit h this retrotransposon should be feasible in rice. Ongoing reverse-genetics studies, such as the PCR-screening of mutants and cataloguing of mutants b y sequencing Tos17-insertion sites, as well as traditional forward-genetics studies, have clearly demonstrated that the Tos17 system can significantly contribute to the functional genomics of rice.