Crops and Soils Research and Development Center, Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd, Quebec, QC, G1V 2J3, Canada.
Theor Appl Genet. 2010 May;120(8):1611-9. doi: 10.1007/s00122-010-1280-2. Epub 2010 Feb 9.
Sequence-related amplified polymorphism (SRAP) analysis was used to uncover genetic polymorphisms among alfalfa populations recurrently selected for superior tolerance to freezing (TF populations). Bulk DNA samples (45 plants/bulk) from each of the cultivar Apica (ATF0), and populations ATF2, ATF4, ATF5, and ATF6 were evaluated with 42 different SRAP primer pairs. Several polymorphisms that progressively intensified or decreased with the number of recurrent cycles were identified. Four positive polymorphisms (F10-R14, Me4-R8, F10-R8 and F11-R9) that, respectively, yielded 540-, 359-, 213-, and 180-bp fragments were selected for further analysis. SRAP amplifications with genotypes within ATF populations confirmed that the polymorphisms identified with bulk DNA samples were reflecting changes in the frequency of their occurrence in response to selection. In addition, the number of genotypes cumulating multiple polymorphisms markedly increased in response to recurrent selection. Independent segregation of the four SRAP polymorphisms suggests location at unlinked loci. Homology search gave matches with BAC clones from syntenic Medicago truncatula for the four SRAP fragments. Analysis of the relationship with low temperature tolerance showed that multiple SRAP polymorphisms are more frequent in genotypes that maintain superior regrowth after freezing. These results show that SRAP analysis of bulk DNA samples from recurrent selections is an effective approach for the identification of genetic polymorphisms associated with quantitative traits in allogamous species. These polymorphisms could be useful tools for indirect selection of freezing tolerance in alfalfa.
序列相关扩增多态性 (SRAP) 分析用于揭示反复选择具有优异抗冻性 (TF 群体) 的紫花苜蓿群体的遗传多态性。用 42 对不同的 SRAP 引物对评估了每个品种 Apica (ATF0) 以及群体 ATF2、ATF4、ATF5 和 ATF6 的 45 株/批的 bulk DNA 样本。鉴定出一些随着反复循环次数增加或减少的多态性。选择了四个正向多态性 (F10-R14、Me4-R8、F10-R8 和 F11-R9)，分别产生 540、359、213 和 180-bp 片段进行进一步分析。在 ATF 群体内的基因型中进行的 SRAP 扩增证实，用 bulk DNA 样本鉴定的多态性反映了其发生频率的变化，这是对选择的响应。此外，随着反复选择，累积多个多态性的基因型数量明显增加。四个 SRAP 多态性的独立分离表明它们位于非连锁基因座上。同源性搜索在同源的 Medicago truncatula 上与 BAC 克隆匹配，得到了四个 SRAP 片段。对低温耐受性的分析表明，在保持抗冻后良好再生的基因型中，多个 SRAP 多态性更为常见。这些结果表明，从反复选择的 bulk DNA 样本中进行 SRAP 分析是一种有效的方法，可用于鉴定与异花授粉物种的数量性状相关的遗传多态性。这些多态性可以作为紫花苜蓿抗冻性间接选择的有用工具。
