Fine Mapping Of Semi-dominant Male Sterility Gene Sg3 In Rice (Oryza Sativa L.)

Male sterility,which is ubiquitous in higher plants,plays an important role in crop breeding and is a main agronomic traits in the study on crop heterosis utilization.The mapping,cloning and mechanism study on semi-dominant male sterility gene is important to the utilization of heterosis in rice.On the basis of previous study,we developed F₂mapping population from the cross between W0?HJX74?and its single segment subsitution lines?SSSLs?with O.glumaepatula as the donor.We designed simple sequence repeats?SSR?markers and InDel markers,and used these markers in fine mapping the semi-dominant male sterility gene Sg3.The main research contents were as follows:Used the SSR markers to select recombinant lines from the segregating population developed from the cross between W0?HJX74?and its single segment subsitution lines?SSSLs?with O.glumaepatula as the donor;Pollen fertility and field seed setting rate analysis of the Sg3 recombinant lines selected above;Designed new primers to narrow down the Sg3 target region.The main results were as follows:Randomly selected 130 plants from the F₂segregating population for pollen fertility and genetic analysis,and found 30 of them showed fertile pollen,75 of them showed semi sterile pollen and 25 of them showed sterile pollen,respectively,fitting 1:2:1 segragation ratio.These results indicated that the segregation distortion of SSR markers and sterility phenotype in the F₂ segragation population was controlled by a semi-dominant male sterility gene?named as Sg3?in chromosome 3;Used mapping software MAPMAKER/QTL 3.0 for linkage analysis of molecular markers and found Sg3 was located between molecular markers RM15423 and RM15440,with the genetic distance of 2.7cM to both markers;Sg3 identified in this study was a new semi-dominant male sterility gene according the published literatures,and the Sg3 SSSL was a new semi-dominant male sterile rice material;InDel markers were designed for fine mapping of Sg3.Finally,the semi-dominant male sterility gene Sg3 was located between markers InDel-38 and RM15440,with genetic distance approximately 1cM,there are 22 candidate genes in the location interval,through gene prediction,we think Os03g0607200?Os03g0607600 and Os03g0608700 are more likely.In this study,we fine-mapped the semi-dominant male sterility gene Sg3 to a 1 cM region,which laid a solid foundation for gene cloning and molecular characterization of Sg3.Our study not only provided valuable material for the study of semi-dominant male sterility line but also enriched the semi-dominant male sterility gene pool.