TRANSPOSON-TAGGING OF RICE GENES WITH A RICE RETROTRANSPOSON Tos17

¹ 943-0193 1-2-1 Inada Jouetu Niigata Japan

² 305-8602 2-1-2 Kannnonndai Tsukuba Ibaraki

Tos17 is a retrotransposon of rice that is active during tissue culture. For transposon-tagging with Tos17, we observed R1 and R2 population regenerated plants of rice cultivars, Nipponbare and Akitakomachi. Genomic southern hybidization analysis was carried out in this population to select mutations which are induced by Tos17 integration in genes. In three years, 3375 lines of R1 generation of the both cultivars were observed. By the observation of the plants from germination stage to maturing stage and thier seeds, 31% of the lines were found to have phenotypic deviaton, which included dwarf, leaf color variation, necrosis, leaf-, panicle-, and plant-morphology variation and grain variation. R2 generation of 207 lines among them were obsesrved for thier segregation to confirm the phenotypic deviation as gene mutation. In this analysis, 53% of the deviated phenotype appeared to be controled by single genes, therefore, they could be mutations. Genomic southern hybidization analysis of 29 of the mutations suggested that eight mutations among them might be induced by Tos17 integration. The flanking sequence of Tos17 inserted sites of these mutant genes, which could be obtained by Tail-PCR, will be used as probes to isolate corresponding wild type genes. We are now taking this cloning procedure in two of these mutations, small grain/semidwarf mutation and wrinkled grai n mutation.