Fine Mapping A Pleiotropic Gene For Grain Shape And Spikelets Per Panicle In Rice,GDS7, And Functional Analysis Of FZP

Grain yield is mainly determined by tiller number, spikelets per panicle (SPP) and1000-grain weight (TGW). Furthermore, the grain quality traits, grain length (GL), grain width (GW) and grain thickness (GT), are the three important affecting components for grain weight. Both grain yield and grain quality traits all are controlled by quantitative trait loci (QTL). In this study, two extremely difference rice varieties in grain size, Nanyangzhan (NYZ) and Chuan7(C7), were used to develop the recombinant inbred lines (RILs) population. F7and F8were derived from the single seed descend from its F2. The genetic linage map was constructed for QTL mapping analysis. A minor QTL (qGL7) for grain length was fine mapped. It has the effects on either GL/TGW or SPP. The larger F2population was employed for fine mapping to further delimit the candidate region, in which there is no reported gene that functions in GL/TGW and/or SPP. Thus, this QTL named GDS7(Grain Dense and Size7). Besides, FZP was focused for bio-function analysis, before it was excluded out of the candidate region of GDS7.1,164SSR makers and185RILs individuals were used to construct the genetic linage map, the map totally covered1635.9cM. The largest gap between two markers in the linage map was30.2cM (located on short arm of the chromosome9). The mean interval between two markers was9.9cM.2, In2006and2007rice growing seasons, F7and Fg were planted respectively in a bird-net-equipped field on the experimental fram of Huazhong Agricultural University in Wuhan. The randomized complete block design with two replicates was adopted in field trials. Several related phenotypes were collected for QTL analysis. Totally,20grain yield and28grain quality QTLs were mapped.20of the all48QTLs were identified in both years.3, Three near isogenic lines with the different genetic background, NIL-GDS7(R76), NIL-GDS7(NYZBG) and NIL-GDS7(C7BG), were developed adopting the strategies of CB-NIL and HIF-NIL, respectively.4, A local linage map was constructed using the NIL-GDS7(R76) F2population. QTL analysis was performed and the score of LOD and explained the phenotype variance were also deduced. The QTL for GL and TGW had a LOD value of42.2and66.8, respectively. They explained the phenotype variance more than61%. Besides, a SPP QTL was also examined and it explained29%of phenotype variance, and the C7allele increased trait value. Furthermore, F3population was planted for progeny test. Finally, this gene was located on between RM6389and RID711with a distance of0.2cM.5, A6000F2population was used for fine mapping GDS7, and FZP was excluded out of the current candidate region.6, The longitudinal section of spikelet was observed and found different cell number was existed between NIL-GDS7two genotype "NN" and "CC".7, Scanning election microscopy was performed for rice transverse sections of two genotypes "NN" and "CC". The images showed a loose arrange pattern of starch granule in genotype of "NN", but it was opposite (compact) in genotype of "CC". Furthermore, the grain filling rates of two genotypes were also compared and found it was more faster in genotype of "NN" than that of "CC".8, A new allele of FZP (fzp-11) was identified. It had a SNP mutant in the domain of AP2/ERF with a phenotype of more secondary branches and absent of spikelet.9, The FZP alleles from Nipponbare and wild rice (Oryza rufipogon) were over-expressed and transformed into fzp-11and Zhonghuall plants, respectively. The results showed the allele from cultivar rice Nipponbare can rescued the mutant phenotype, but the allele from wild rice can not.10, RFL, LAX1and some of OsMADS-box genes had a differential expression levels between wild type and fzp-11, which were examined in both Real-Time PCR and microarray. The expression levels of some of them were also analyzed in the over-expressed transgenic plants.11,80cultivar rice and36wild rice were respectively collected for FZP encoding sequence examination. There was no any difference between cultivar rice. But, among the wild rice, some Insert, Delete and SNP were happened in the regions exclude out of AP2/ERF domain.