Development of near-isogenic lines of wheat carrying different null Wx alleles and their starch properties
Development of near-isogenic lines of wheat carrying different null Wx alleles and their starch properties
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DOI：
10.1023/a:1015042322687
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发表时间：
2002-01-01
期刊：
影响因子：
1.9
通讯作者：
Komae, K
中科院分区：
文献类型：
--
作者：
Miura, H;Wickramasinghe, MHA;Komae, K
由 Wx 基因编码的颗粒结合淀粉合酶 (GBSS I) 参与直链淀粉合成。为了分析六倍体小麦中直链淀粉合成机制和相关淀粉特性，具有共同遗传背景的 Wx 基因座上三个无效等位基因的不同组合的八种可能的基因型是先决条件。使用小麦x玉米方法从中国春x蜡质中国春F-1植物产生双单倍体(DH)系的近等基因群体。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳检查DH后代的Wx蛋白表型，发现三个Wx基因座中每一个的无效等位基因以孟德尔方式分离。田间试验表明，八种类型之间的出穗时间、株高和籽粒产量性状没有差异。胚乳淀粉中的直链淀粉含量在野生型中最高，而在不含Wx蛋白的蜡质型中最低。单无效型和双无效型的比较表明Wx-A1a等位基因的直链淀粉合成能力最低。淀粉的糊化性能以蜡质型最高，其次是双空型。因此，峰值粘度和分解都与直链淀粉含量呈负相关。支链淀粉结构的链长分布分析显示八种类型之间没有明显差异，这表明由于无效Wx等位基因渗入而导致的GBSS I活性降低不会影响支链淀粉的链长或支化程度。
The granule-bound starch synthase (GBSS I) encoded by the Wx genes, is involved in amylose synthesis. For analyses of mechanisms of amylose synthesis and associated starch properties in hexaploid wheat, eight possible genotypes having different combinations of the three null alleles at the Wx loci with a common genetic background are a prerequisite. A near-isogenic population of doubled haploid (DH) lines was produced from Chinese Spring x waxy Chinese Spring F-1 plants using the wheat x maize method. The Wx protein phenotypes of the DH progeny were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and found that the null alleles at each of the three Wx loci segregated in a Mendelian fashion. A field trial demonstrated no differences between the eight types for ear emergence time, plant height and grain yield traits. Amylose content in the endosperm starch was highest in the wild type while lowest in the waxy type having no Wx proteins. Comparison between single null types and double null types indicated that the amylose synthesis capacity of Wx-A1a allele is the lowest. Pasting properties of starch are the highest in the waxy type, followed by the double null types. Consequently, both peak viscosity and breakdown were negatively correlated with amylose content. The chain-length distribution analysis of amylopectin structure revealed no clear difference among the eight types, suggesting that the reduced GBSS I activity due to introgression of the null Wx alleles does not affect either the chain length or the degree of branching of amylopectin.