Development Of An Ethylmethane Sulphonate Mutant Library Using Rice Variety Kong Yu 131

Rice(Oryza sativa) is an important food crop and also the model plant of cereal crop and monocotyledons for functional genome research. With the completion of the rice genome sequencing, the research which aim at parsing the function of rice gene develops rapidly. The large mutant library is an important platform for comprehensive gene research on whole genome level. Our laboratory has ever established a large-scale T-DNA insertion mutant library, and have studied a number of genes’ function with T-DNA mutant library, which plays an important role in rice functional genome research around the world. However, it couldn’t ensure all genes obtaining themselves’ insertion mutant due to the limitation of T-DNA inserting density. Along with the "rice 2020" plan was put forward, in order to know the function of every gene, it is urgent to establish a saturated whole-genome mutant library and a platform which screen the target genes.We induced Kong yu 131 which is one of the largest conventional rice varieties in northeast China with 0.81% EMS(V/V), and developed a EMS mutagenized population. Major results are described as follows:1. We have screened 8770 M2 families, and gained 2215 typical mutant lines contain of plant type, heading period, spike type and fertility, the mutation frequency was 25.25%. And 18 mutant materials showed obvious improvement character compared with wild type, which have prospects in breeding variety.We planted M3 to observe the improved traits whether have stable heredity, at least one family showed stable character. And then investigated the agronomic trait of this family, we found except the tiller number, other traits such as panicle length, the primary branch number, the secondary branch number,every panicle grain number, the yield of each panicle and the yield of every plant were obviously increased.2. At present, we have constructed a seed library which contains 8448 M2 families,have extracted 6720 DNA and finished tridimensional pooling. By reverse genetic screening 8 published genes PI21, GS3, TRZ2, RR22, CSA, GW8,TMS5 and mi R156-e, we have obtained 132 mutants, the mutation frequency of DNA level was 1/301 kb.3. We proceeded to whole genome sequencing among M2 mutant plant, M2 individual plant and wild type, the sequencing depth was 20, and then chose the region which sequencing depth is more than 15 to count the base mismatch, we discovered 36465 and 1794 SNP variation, respectively. The average mutation frequency of group level was 1/11 kb.