Institute of Crop Science, National Wheat Improvement Center/The National Key Facility for Crop Genetic Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing 100081, China.
BMC Plant Biol. 2010 Jun 24;10:124. doi: 10.1186/1471-2229-10-124.
Low-molecular-weight glutenin subunits (LMW-GS) play a crucial role in determining end-use quality of common wheat by influencing the viscoelastic properties of dough. Four different methods - sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2-DE, IEF x SDS-PAGE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR), were used to characterize the LMW-GS composition in 103 cultivars from 12 countries.
At the Glu-A3 locus, all seven alleles could be reliably identified by 2-DE and PCR. However, the alleles Glu-A3e and Glu-A3d could not be routinely distinguished from Glu-A3f and Glu-A3g, respectively, based on SDS-PAGE, and the allele Glu-A3a could not be differentiated from Glu-A3c by MALDI-TOF-MS. At the Glu-B3 locus, alleles Glu-B3a, Glu-B3b, Glu-B3c, Glu-B3g, Glu-B3h and Glu-B3j could be clearly identified by all four methods, whereas Glu-B3ab, Glu-B3ac, Glu-B3ad could only be identified by the 2-DE method. At the Glu-D3 locus, allelic identification was problematic for the electrophoresis based methods and PCR. MALDI-TOF-MS has the potential to reliably identify the Glu-D3 alleles.
PCR is the simplest, most accurate, lowest cost, and therefore recommended method for identification of Glu-A3 and Glu-B3 alleles in breeding programs. A combination of methods was required to identify certain alleles, and would be especially useful when characterizing new alleles. A standard set of 30 cultivars for use in future studies was chosen to represent all LMW-GS allelic variants in the collection. Among them, Chinese Spring, Opata 85, Seri 82 and Pavon 76 were recommended as a core set for use in SDS-PAGE gels. Glu-D3c and Glu-D3e are the same allele. Two new alleles, namely, Glu-D3m in cultivar Darius, and Glu-D3n in Fengmai 27, were identified by 2-DE. Utilization of the suggested standard cultivar set, seed of which is available from the CIMMYT and INRA Clermont-Ferrand germplasm collections, should also promote information sharing in the identification of individual LMW-GS and thus provide useful information for quality improvement in common wheat.
低分子量谷蛋白亚基（LMW-GS）通过影响面团的粘弹性来决定普通小麦的食用品质，在其中起着至关重要的作用。使用四种不同的方法 - 十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）、二维凝胶电泳（IEF x SDS-PAGE）、基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF-MS）和聚合酶链反应（PCR），对来自 12 个国家的 103 个品种的 LMW-GS 组成进行了表征。
在 Glu-A3 位点，通过 2-DE 和 PCR 可以可靠地鉴定出所有 7 个等位基因。然而，基于 SDS-PAGE，等位基因 Glu-A3e 和 Glu-A3d 分别不能常规地区分 Glu-A3f 和 Glu-A3g，而等位基因 Glu-A3a 不能通过 MALDI-TOF-MS 与 Glu-A3c 区分。在 Glu-B3 位点，等位基因 Glu-B3a、Glu-B3b、Glu-B3c、Glu-B3g、Glu-B3h 和 Glu-B3j 可以通过所有四种方法清楚地识别，而 Glu-B3ab、Glu-B3ac、Glu-B3ad 只能通过 2-DE 方法识别。在 Glu-D3 位点，电泳和 PCR 等位基因鉴定存在问题。MALDI-TOF-MS 具有可靠鉴定 Glu-D3 等位基因的潜力。
PCR 是鉴定育种计划中 Glu-A3 和 Glu-B3 等位基因最简单、最准确、成本最低的方法，因此推荐使用。需要结合多种方法来鉴定某些等位基因，当对新等位基因进行表征时尤其有用。选择了 30 个标准品种作为集合中的所有 LMW-GS 等位基因变体的代表。其中，中国春、Opata 85、Seri 82 和 Pavon 76 被推荐为 SDS-PAGE 凝胶使用的核心品种。Glu-D3c 和 Glu-D3e 是相同的等位基因。通过 2-DE 鉴定到两个新的等位基因，即品种 Darius 中的 Glu-D3m 和 Fengmai 27 中的 Glu-D3n。利用建议的标准品种集，其种子可从 CIMMYT 和 INRA 克莱蒙费朗种质资源库获得，也应该促进个体 LMW-GS 鉴定信息的共享，从而为普通小麦的品质改良提供有用信息。
