Fine mapping of a quantitative trait locus for grain number per panicle from wild rice (Oryza rufipogon Griff.)
Fine mapping of a quantitative trait locus for grain number per panicle from wild rice (Oryza rufipogon Griff.)
复制标题
DOI：
10.1007/s00122-006-0326-y
复制
发表时间：
2006-08-01
影响因子：
5.4
通讯作者：
Sun, Chuan Qing
中科院分区：
文献类型：
--
作者：
Tian, Feng;Zhu, Zuofeng;Sun, Chuan Qing
SIL040 是一种基因渗入系 (IL)，通过将普通野生稻 (Oryza rufipogon) 的染色体片段渗入籼稻品种桂超 2 号而开发，其每穗粒数显着低于轮回亲本桂超 2 号。SIL040 与桂超 2 号杂交衍生的 F-2 和 F-3 代数量性状位点 (QTL) 分析显示，gpa7、位于 7 号染色体短臂上的 QTL 是造成这种变异的原因。来自普通野生稻的等位基因降低了每穗粒数。为了对gpa7进行精细定位，利用gpa7侧翼标记构建了包含1,966株SIL040与桂超2号杂交衍生的F-2植株的高分辨率图谱，并对筛选的重组体衍生的每个F-3家族的主穗结构进行了详细的定量评估。通过两步替换作图，gpa7最终被缩小到35 kb的区域，其中包含栽培稻中的5个预测基因。 5个穗性状（穗长、每穗一级枝、每穗二级枝、一级枝上的粒数和二级枝上的粒数）的QTL均与gpa7在同一区间内作图，表明该位点与穗结构相关，表现出多效性。 IL SIL040穗部结构表征进一步表明，在gpa7从普通野生等位基因向栽培稻1驯化过程中，不仅每穗分枝数和粒数显着增加，更重要的是，每穗次生分枝数占每穗总分枝数的比例以及每穗次生分枝粒数占每穗总粒数的比例均显着增加。所有这些结果都证实了gpa7可能在水稻穗驯化过程中对每穗粒数和每穗次生分枝比例的调节发挥重要作用。
SIL040, an introgression line (IL) developed by introgressing chromosomal segments from an accession of Oryza rufipogon into an indica cultivar Guichao 2, showed significantly less grains per panicle than the recurrent parent Guichao 2. Quantitative trait locus (QTL) analysis in F-2 and F-3 generations derived from the cross between SIL040 and Guichao 2 revealed that gpa7, a QTL located on the short arm of chromosome 7, was responsible of this variation. Alleles from O. rufipogon decreased grains per panicle. To fine mapping of gpa7, a high-resolution map with 1,966 F-2 plants derived from the cross between SIL040 and Guichao 2 using markers flanking gpa7 was constructed, and detailed quantitative evaluation of the structure of main panicle of each of F-3 families derived from recombinants screened was performed. By two-step substitution mapping, gpa7 was finally narrowed down to a 35-kb region that contains five predicted genes in cultivated rice. The fact that QTLs for five panicle traits (length of panicle, primary branches per panicle, secondary branches per panicle, grains on primary branches and grains on secondary branches) were all mapped in the same interval as that for gpa7 suggested that this locus was associated with panicle structure, showing pleiotropic effects. The characterizing of panicle structure of IL SIL040 further revealed that, during the domestication from common wild allele to cultivated rice one at gpa7, not only the number of branches and grains per panicle increased significantly, more importantly, but also the ratio of secondary branches per panicle to total branches per panicle and the ratio of grains on secondary branches per panicle to total grains per panicle increased significantly. All these results reinforced the idea that gpa7 might play an important role in the regulation of grain number per panicle and the ratio of secondary branches per panicle during the domestication of rice panicle.