Global Selection on Sucrose Synthase Haplotypes during a Century of Wheat Breeding1[C][W]
Global Selection on Sucrose Synthase Haplotypes during a Century of Wheat Breeding1[C][W]
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DOI：
10.1104/pp.113.232454
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发表时间：
2014-04-01
期刊：
影响因子：
7.4
通讯作者：
Zhang, Xueyong
中科院分区：
文献类型：
--
作者：
Hou, Jian;Jiang, Qiyan;Zhang, Xueyong
单位面积穗数、每穗粒数和千粒重是重要的产量构成因素。在中国看来，小麦产量的增加主要是由于穗粒数和千粒重的增加。千粒重主要取决于淀粉含量，因为淀粉约占籽粒胚乳的70%。蔗糖合成酶催化是蔗糖转化为淀粉的第一步，即分别位于7A/7B/7D和2A/2B/2D上的小麦蔗糖合成酶基因(TaSus1和TaSus2)将蔗糖转化为果糖和UDP-葡萄糖。共有1,520份小麦材料在这6个基因座上进行了基因分型。在TaSus2-2A、TaSus2-2B、TaSus1-7A和TaSus1-7B基因座上分别检测到2、2、5和2种单倍型。它们的主要变异是在内含子中检测到的。核心种质中的348个现代中国品种的单倍型与千粒重相关的单倍型差异显著。从上个世纪初开始，中国、欧洲和北美等地的优良单倍型的频率变化呈现出逐渐增加的趋势。研究了全球6个小麦主产区小麦优势单倍型的地理分布和时间变化。小麦多倍化驯化和育种过程中出现了较强的单倍型选择瓶颈。同一基因座上单倍型间的遗传效应差异影响选择的时间和强度。本研究表明，胚乳淀粉合成途径是全球小麦高产育种中间接选择的主要目标。
Spike number per unit area, number of grains per spike, and thousand kernel weight (TKW) are important yield components. In China, increases in wheat (Triticum aestivum) yields are mainly due to increases in grain number per spike and TKW. TKW mainly depends on starch content, as starch accounts for about 70% of the grain endosperm. Sucrose synthase catalysis is the first step in the conversion of sucrose to starch, that is, the conversion of sucrose to fructose and UDP-glucose by the wheat sucrose synthase genes (TaSus1 and TaSus2) that are located on chromosomes 7A/ 7B/ 7D and 2A/ 2B/ 2D, respectively. A total of 1,520 wheat accessions were genotyped at the six loci. Two, two, five, and two haplotypes were identified at the TaSus2-2A, TaSus2-2B, TaSus1-7A, and TaSus1-7B loci, respectively. Their main variations were detected within the introns. Significant differences between the haplotypes correlated with TKW differences among 348 modern Chinese cultivars from the core collection. Frequency changes for favored haplotypes showed gradual increases in cultivars released since beginning of the last century in China, Europe, and North America. Geographic distributions and time changes of favored haplotypes were characterized in six major wheat production regions worldwide. Strong selection bottlenecks to haplotype variations occurred at polyploidization and domestication and during breeding of wheat. Genetic-effect differences between haplotypes at the same locus influence the selection time and intensity. This work shows that the endosperm starch synthesis pathway is a major target of indirect selection in global wheat breeding for higher yield.