Improving Several Yield Related Traits By Genome Editing In Rice

Improving rice yield-related traits for increasing rice yield was one of the most important contents in rice breeding.The uncertainty and blindness of the traditional hybrid method to improve the yield characters limited the level of rice yield breeding.With application of a large number of rice yield-related genes cloned and some biotechnology methods,especially,development of genome editing technology in recent years,it became possible to directionally improve yield-related traits in rice.This thesis intended to directionally make everal genes controling important agronomic traits mutation in ricee and to produce a series of mutants related genes,and by phenotype observation,to study the possibility and characteristics of the traits genetically modified and create some new materials with excellent mutant alleles.The main results are as follows:IPA1,which is a key gene controling plant architecture in rice,was mutated using TALENs technology in Minghui 86,an elite restorer in three-line hybrid rice.The eight mutants with different sequences were obtained by contiuous subculture and differentiation of resistant calli.By self-cross and PCR analysis,the expression box of the TALENs was removed and three homozygous mutants,which IPA1 gene sequences were deleted 2bp,4bp and 23bp respectively,were obtained with transgene free.It was found that IPA1 mutation(deleted 4bp)could significantly alter the rice plant height and tiller number.Plant height was significantly reduced and homozygous mutant was dwarfed by an average of 25.5cm and tiller number was significantly increased in homozygous mutant by an average of 4.7.Under the genetic background of Minghui 86,the plant height in homozygous mutant was 94.1cm and the tiller number in homozygous mutant was 12.5.Using CRISPR/Cas9 system,we directionally knocked out three panicle type genes DEP1,DEP3 and OsLAC in rice.The transgenic plants with genome editing vector,were screened and 4 DEP1 mutations,28 DEP3 mutations and 6 OsLAC mutations were obtained.Of which expression frame of CRISPR/Cas9 system was removed in DEP1 and DEP3 mutants.Preliminary analysis of phenotype in the mutants showed that panicle grain density and length increased and grain size became small in dep1 mutants,and only the homozygous dep3 mutant with 300bp deletion was significantly difference from wildtype in phenotype,which panicle grains,density and length increased,and grain length width ratio increased by 3.2 in the dep3 mutant.Phenotype of the OsLAC mutants,further analysis of phenotype in dep1 and dep3 mutants,and causes of phenotype differences in dep3 different mutants are under way.