基于染色体片段置换系的野生稻粒宽QTL-qGW8.1的精细定位

Fine Mapping of a Wild Rice Grain Width QTL-qGW8.1 Using a Chromosome Segment Substitution Line

利用以栽培稻9311为受体、普通野生稻为供体的染色体单片段置换系CSSL182,检测到一个与粒宽相关的QTL。CSSL182与受体亲本9311粒型性状差异显著,且只在8号染色体有一个野生稻导入片段。构建CSSL182/9311的F_2次级分离群体,将粒宽QTL初定位在8号染色体的标记RM447和RM264之间,贡献率达22.49%,将该QTL命名为qGW8.1。随后进一步设计区间内多态性分子标记引物,检测F_2群体的2000株分离个体以及F_(2∶3)群体交换单株,结合后代表型验证,最终将qGW8.1精细定位到8号染色体10 kb区间内。该区间内含有3个候选基因,基因测序发现这3个基因在双亲之间均含有丰富的变异。对双亲子粒颖壳细胞电镜扫描观察发现,CSSL182的颖壳细胞宽度比9311减少16.7%。这一结果表明qGW8.1中来自野生稻的等位基因通过改变颖壳细胞形状影响粒型。

In the study, one chromosome single segment substitution line（ CSSL）, CSSL182 which developed from cultivated rice 9311 as the receptor parent and common wild rice （ Oryza rufipogon Griff. ） as the donor parent, was selected for grain shape QTL identification. The CSSL182 has significant shorter grain width and lighter grain weight compared with receptor parent 9311. We constructed a CSSL182/9311 F2 population,one QTL associated with grain width was located between RMd47 and RM264 on Chr. 8 and then was named qGW8. 1. Using additional molecular markers,2000 F2 individuals and F3 recombinant plants were detected and then qGWS. ! was finally fine mapped to a 10 kb region. DNA sequencing found that 3 candidate genes were located in this region. The electron microscope scanning showed that width of CSSL182＇s glumes cell was 16. 7 % narrower than 9311＇s, indicated that the alleles from wild rice might control grain width by affecting glumes cell shape.