Waxy phenotype evolution in the allotetraploid cereal broomcorn millet: mutations at the GBSSI locus in their functional and phylogenetic context.
Waxy phenotype evolution in the allotetraploid cereal broomcorn millet: mutations at the GBSSI locus in their functional and phylogenetic context.
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DOI：
10.1093/molbev/mss209
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发表时间：
2013-01
影响因子：
10.7
通讯作者：
Trafford K
中科院分区：
文献类型：
--
作者：
Hunt HV;Moots HM;Graybosch RA;Jones H;Parker M;Romanova O;Jones MK;Howe CJ;Trafford K
许多驯化谷物中都存在蜡质突变体，其中胚乳淀粉含有〜100%支链淀粉，而不是野生型的〜70%支链淀粉和〜30%直链淀粉。糯性品种的种植集中在东亚，那里对糯性食品的烹饪偏好可能是从古代食品加工传统中发展而来的。蜡状表型是 GBSSI 基因突变的结果，该基因催化直链淀粉合成。高粱或黍（Panicum miliaceum L.）是世界上最古老的栽培谷物之一，在史前早期就传播到欧亚大陆。最近的系统发育地理学分析显示出强大的遗传结构，这可能反映了古代的扩张模式。黍是一种非常不寻常的全蜡质异源四倍体谷物。之前的工作描述了两个同源 GBSSI 位点，每个位点都有多个等位基因，但无法确定这两个位点是否都对 GBSSI 功能有贡献。我们首先测试了两个 GBSSI 位点对直链淀粉合成的相对贡献，然后测试了 GBSSI 等位基因与从简单序列重复 (SSR) 推断的系统发育结构之间的关联。我们通过测定淀粉组成和蛋白质功能来评估黍中所有已知 GBSSI 基因型的表型。结果表明，GBSSI-S基因座是控制胚乳直链淀粉含量的主要基因座，而GBSSI-L基因座则强烈降低合成能力。我们对来自欧亚大陆地方品种的 178 个个体的 2 个 GBSSI 和 16 个 SSR 位点进行了基因分型，并分析了系统发育地理学结构以及 GBSSI 等位基因的地理和系统发育分布。我们发现 GBSSI 等位基因具有独特的空间分布，并且与 SSR 定义的特定遗传簇有很强的关联性。导致部分蜡质表型的等位基因组合在地方品种群体中不存在。我们的数据表明，黍是负责谷物直链淀粉的 GBSSI 基因座正处于二倍化过程中的系统。突变等位基因显示出遗传群体之间的一些交换，这受到特定区域蜡状表型的选择的青睐。部分蜡质表型可能被选择反对——这一意外的发现表明，需要更好地理解这种区分东西方文化中谷物使用的现象的人类生物学。
Waxy mutants, in which endosperm starch contains ∼100% amylopectin rather than the wild-type composition of ∼70% amylopectin and ∼30% amylose, occur in many domesticated cereals. The cultivation of waxy varieties is concentrated in east Asia, where there is a culinary preference for glutinous-textured foods that may have developed from ancient food processing traditions. The waxy phenotype results from mutations in the GBSSI gene, which catalyzes amylose synthesis. Broomcorn or proso millet (Panicum miliaceum L.) is one of the world’s oldest cultivated cereals, which spread across Eurasia early in prehistory. Recent phylogeographic analysis has shown strong genetic structuring that likely reflects ancient expansion patterns. Broomcorn millet is highly unusual in being an allotetraploid cereal with fully waxy varieties. Previous work characterized two homeologous GBSSI loci, with multiple alleles at each, but could not determine whether both loci contributed to GBSSI function. We first tested the relative contribution of the two GBSSI loci to amylose synthesis and second tested the association between GBSSI alleles and phylogeographic structure inferred from simple sequence repeats (SSRs). We evaluated the phenotype of all known GBSSI genotypes in broomcorn millet by assaying starch composition and protein function. The results showed that the GBSSI-S locus is the major locus controlling endosperm amylose content, and the GBSSI-L locus has strongly reduced synthesis capacity. We genotyped 178 individuals from landraces from across Eurasia for the 2 GBSSI and 16 SSR loci and analyzed phylogeographic structuring and the geographic and phylogenetic distribution of GBSSI alleles. We found that GBSSI alleles have distinct spatial distributions and strong associations with particular genetic clusters defined by SSRs. The combination of alleles that results in a partially waxy phenotype does not exist in landrace populations. Our data suggest that broomcorn millet is a system in the process of becoming diploidized for the GBSSI locus responsible for grain amylose. Mutant alleles show some exchange between genetic groups, which was favored by selection for the waxy phenotype in particular regions. Partially waxy phenotypes were probably selected against—this unexpected finding shows that better understanding is needed of the human biology of this phenomenon that distinguishes cereal use in eastern and western cultures.
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影响因子：
3.9
作者：
NEI, M;TAJIMA, F;TATENO, Y
通讯作者：
TATENO, Y
影响因子：
7.4
作者：
Patron, NJ;Smith, AM;Denyer, K
通讯作者：
Denyer, K
影响因子：
2
作者：
Araki, Mie;Numaoka, Aya;Fukunaga, Kenji
通讯作者：
Fukunaga, Kenji
影响因子：
8.8
作者：
Karlsson, Malin E.;Leeman, A. Margareta;Eliasson, Ann-Charlotte
通讯作者：
Eliasson, Ann-Charlotte
影响因子：
3.8
作者：
Akerberg, A;Liljeberg, H;Bjorck, I
通讯作者：
Bjorck, I