Mapping Of The Thermo-sensitive Genic Male Sterility Gene Tms9-1in Rice And The Effect Of Monosaccaride Transporter Genes On Fertility And Grain Filling

Photoperiod-thermo-sensitive genic male sterility line is an important germplasm resource for the two-line hybrid breeding system, which plays a very critical role in the development of rice yield using the heterosis. The P/TGMS gene is the major factor that controls the fertility conversion of P/TGMS lines. The previous study showed that P/TGMS gene was distributed on the different rice chromosomes except for4and11chromosomes, and the mechanism involved in P/TGMS gene could also be different. In this study, HengnongS-1is one of the oldest TGMS lines and the fertility was sensitive to environmental temperature. Our genetic analysis showed that the TGMS gene in HengnongS-1was controlled by a single recessive gene that was non-allelic with the other TGMS loci identified, including C815S, ZhulS and Y58S. Using SSR markers and bulked segregant analysis, we located the TGMS locus on chromosome9and named the gene tms9-1. At the same time, the tms9-1locus was further narrowed down to a162kb interval between two dCAPS markers. According to the results of gene annotation database and sequence analysis revealed that a T to C substitution on the third exon of OsMS1gene results in an amino acid change from in the tms9-1candidate gene (Os09g27620) in HengnongS-1. Sequencing of other rice accessions, including P/TGMS lines, conventional indica varieties and japonica varieties, showed that this SNP was exclusive to HengnongS-1. So we speculate that the OsMS1gene was the candidate gene for the tms9-1. The expression analysis showed that the pattern was same between Minghui63and HengnongS-1by RT-PCR and the SNP could not change the expression trait of OsMSl gene. The OsMS1gene was particularly expressed in the spikelet, but hardly detected in the other tissues including of leaf and stem. OsMS1gene has the transient expression characteristic by the search results in the RiceXPro database. OsMSl gene was highly expressed in the anther when the anther was1-3mm but hardly detected in other tissues and period, so we can speculate that the OsMS1gene was related to the development of anther and pollen. The amino acid sequence of OsMS1homolog in different plant species share high identity, suggesting their conserved functions in regulation of male fertility. The SNP in the HengnongS-1is located at the central of a predicated transcription factor which can regulate the transcription elongation by RNA polymerase II. Moreover, a shifting mutation in OsMSl gene was found in the ptcl mutant, and the loss of PTC1function will ultimately result in complete male sterility. Therefore, our study identified a novel TGMS locus and will facilitate the molecular functional dissection of the tms9-1gene. Moreover, the markers linked to the tms9-1gene will provide useful tools for the development of new TGMS lines by marker-assisted selection in two-line hybrid rice breeding programs.Due to the fact that75-90%of the final dry weight of rice grain is comprised of starch, starch biosynthesis and accumulation by grains is a major process that determines the final grain yield. The sucrose, produced by photosynthetic source tissues including of leaf, stem and leaf sheath, is transported via the long-distance phloem pathway to the grain sink tissue where it is cleaved into UDP-glucose and fructose catalyzed by sucrose synthase (SUS) or into glucose and fructose by invertase (INV). Plant monosaccharide transporters mediate the membrane transport of a variable range of monosaccharides, which plays a crucial role in the cell-to-cell and long-distance distribution of sugars throughout the plant. Monosaccharide transporters exist in plant in large gene families. In currently, OsMST4, OsMST5and OsMST6have been proved to be functional monosaccharide transport, but the function of other monosaccharide transporters is also obscure. The expression of OsMST4, OsMST5, OsMST6and OsMST8were changed by overexpression and RNAi technology, we found that the1000grain weight and length-width ratio were also altered compared with CK, so we speculate that the monosaccharide gene have an important function in the course of rice grain filling in the transgenic plants. We also found that the seed setting percentage was decreased in the the OsMST8overexpression transgenic plant lines, suggesting that co-suppress could be happen after the OsMST8gene was overexpressed and the transgenic plants could be sensitive to environmental stress, but those need to be further study to explanation.