Lu Li, Shao Di, Qiu Xianjin, Sun Liang, Yan Wenhao, Zhou Xiangchun, Yang Lin, He Yuqing, Yu Sibin, Xing Yongzhong
National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China.
New Phytol. 2013 Dec;200(4):1269-80. doi: 10.1111/nph.12430. Epub 2013 Aug 16.
The size of cultivated rice (Oryza sativa) grains has been altered by both domestication and artificial selection over the course of evolutionary history. Several quantitative trait loci (QTLs) for grain size have been cloned in the past 10 yr. To explore the natural variation in these QTLs, resequencing of grain width and weight 2 (GW2), grain size 5 (GS5) and QTL for seed width 5 (qSW5) and genotyping of grain size 3 (GS3) were performed in the germplasms of 127 varieties of rice (O. sativa) and 10-15 samples of wild rice (Oryza rufipogon). Ten, 10 and 15 haplotypes were observed for GW2, GS5 and qSW5. qSW5 and GS3 had the strongest effects on grain size, which have been widely utilized in rice production, whereas GW2 and GS5 showed more modest effects. GS5 showed small sequence variations in O. sativa germplasm and that of its progenitor O. rufipogon. qSW5 exhibited the highest level of nucleotide diversity. GW2 showed signs of purifying selection. The four grain size genes experienced different selection intensities depending on their genetic effects. In the indica population, linkage disequilibrium (LD) was detected among GS3, qSW5 and GS5. The substantial genetic variation in these four genes provides the flexibility needed to design various rice grain shapes. These findings provide insight into the evolutionary features of grain size genes in rice.
在进化历史过程中，栽培稻（Oryza sativa）籽粒大小因驯化和人工选择而发生了改变。在过去10年里，已克隆出多个控制籽粒大小的数量性状基因座（QTL）。为探究这些QTL的自然变异情况，对127个水稻（O. sativa）品种的种质资源以及10 - 15份野生稻（Oryza rufipogon）样本进行了粒宽和粒重2（GW2）、粒型5（GS5）、种子宽度5的QTL（qSW5）的重测序以及粒型3（GS3）的基因分型。在GW2、GS5和qSW5中分别观察到10种、10种和15种单倍型。qSW5和GS3对籽粒大小影响最强，已在水稻生产中广泛应用，而GW2和GS5的影响相对较小。GS5在栽培稻种质资源及其祖先野生稻中序列变异较小。qSW5表现出最高水平的核苷酸多样性。GW2呈现出纯化选择的迹象。这四个籽粒大小基因因其遗传效应而经历了不同的选择强度。在籼稻群体中，检测到GS3、qSW5和GS5之间存在连锁不平衡（LD）。这四个基因丰富的遗传变异为设计各种水稻粒型提供了所需的灵活性。这些发现为了解水稻籽粒大小基因的进化特征提供了依据。
