Genetic Analysis And Gene Mapping Of Three Mutants Involved In Reproductive Development In Rice (Orzay Sativa L)

Genetic Analysis And Gene Mapping of Three Mutants Involved In Reproductive Development In Rice (O. Sativa L)The acquisition and research of the rice mutants related to reproductive development played an important role in uncovering the function and interaction of genes in reproductive, especially floral development process. Three rice mutants called ps2 (pistilloid-stamen-2),ohs1 (open hull sterile 1) and frol (function of reproductive organ 1) were found in progenies of transgenic Minghui 86, which is a elite indica restorer line, and genes related to these mutants were tentatively named as ps2(t), ohs1(t) and fro1(t) respectively. We have conducted studies on phenotypic observation, genetic analysis and gene mapping of the three mutants. Major results are as follows:Mutant fro1 can be observed heading but not flowering. Floret shape of fro1 mutant is similar to that of tiny green capsicum, and in which stamens and pistils are abnormal, translucent and sterile. The ps-2 mutant showed that lemma and palea were degenerated, and became narrow and hard like rice ps mutant reported by Luo et al. in 2006. All stamens had been transformed into pistilloid-stamen, and infrequently with one stamen not changed into pistil, and there are more than 10 pistils in the ps-2 mutants. The ohs1 mutant is open hull. Its palea slightly bended toward lemma, and the configuration of stamens and pistils are smaller than that of wild type rice. Also ohs1 is sterile because of no fertile anthers.Genetic analysis indicated that fro1,ps-2 and ohs1 mutants were all controlled by a single recessive gene, respectively. We obtained a dual-mutant fro1fro1/ps-2ps-2 from the crossed progeny of Fro1fro1/PS-2ps-2. Floral structures of these dual mutants were like that of ps-2 mutants, and similar to fro1 mutant in shape. The phenotypic characteristics hinted that gene fro1 and ps-2 might have an interaction each other, and PS-2 might be partly epistasis effects to FRO1. All these results implied ps-2 might be an identity gene for rice floral organ structure, and fro1 for rice function of reproductive organ involved in formation of reproductive cells.In order to map the three mutant genes ps2,ohs1 and fro1, three F2 populations were developed from the crosses of ps2 and 93-11, ohs1 and 93-11 or zhonghua16, fro1 and 93-11. We detected molecular markers linked with the gene of ps2(t), ohs1(t) and fro1(t) using SSR marker technique and BSA (bulked segregated analysis) strategy.Tow SSR markers RM3252 and RM3453 on chromsomel were found to link with ps2(t) gene and located on tow sides of ps2(t) gene. This mapping area was the same as ps gene which had published in 2006. It was suggested that ps2(t) and ps genes might be the same gene。Four SSR markers RM493,NSSR0115,NSSR0107 and RM5638 on chromsomel were detected to link with ohs1(t) gene. RM493 was on one side of ohs1(t) with genetic distance of 7.8 cM, and NSSR0115,NSSR0107 and RM5638 were on the other side with 0.35 cM, 1.3 cM and 2.1 cM respectively.90 of 406 SSR markers showed polymorphism between fro1 and 93-11. However, no marker was detected to link with fro1(t), and mapping of fro1(t) is under way.