Fine Mapping Of A Novel Thermo-sensitive Genic Male Sterility Gene Tms7Derived From The Progeny Of Hybridization Between Cultivated Rice (Oryza Sativa L.) And Wild Rice (Oryza Rufipogon Griff.)

Hybrid rice contributed greatly to enhance yield and to ensure global food security in the past. There are, however, limitations, relatively complex breeding procedure, negative effect of cytoplasm from sterile line and potential risks of single cytoplasm, in traditional three-line breeding. The discovery of photo-thermo-sensitive genic male sterility rice (PTGMS) by Shi Mingsong in1973shed lights on the probability of two-line rice research. Two-line breeding has unique predominance, whereas, the unstability of PTGMS and its restriction conferred by season and region depend on molecular mechanism research of PTGMS. In this research, a thermo-sensitive genic male sterile gene was fine mapped by us, laying foundations for clone of the gene, disclosing related molecular mechanisms and exploring markers for marker-assisted selection breeding of the gene.tms7from thermo-sensitive genic male sterility rice, tb2s, was initially mapped on chromosome9by former experiment. In order to extend mapping, F2population of two cross combinations, tb2s×Zhong1159and Hengnong S-1×Zhong1159were analyzed by15polymorphic markers, delineating tms7gene between markers RM24454and Indel3, with a physical distance of46.5kb. Two Indel markers, Indel1and Indel2, were co-segregated with tms7.Within the region of46.5kb, ten predicted ORFs was found by GeneMark. By referencing rice genome annotation of Nipponbare,5candidate genes detected and one of them, LOC_Os09g27650, has two gene models. To identify the candidate gene of tms7, sequencing analysis of tb2s based on the level of genomic DNA and cDNA was conducted. Nevertheless, no reliable mutation was identified.Re-sequencing of tb2s was used for further identification of candidate gene since no reliably mutant site was confirmed. Every parameter of sequencing results indicates its high quality and reliability. Three of five candidate genes were found in the re-sequencing result of tb2s, which differed in regulation region and open reading fragment with comparison with the genome sequence of9311. All the results will be favorable to find mutant site and real candidate gene, laying a good foundation for complementary experiment and cloning of tms7.