黄瓜全雌性基因连锁的AFLP和SCAR分子标记

 本研究以全雌品种‘戴多星’自交系和弱雌品种‘北京截头’自交系为双亲杂交获得F₁ ,然后得到F₂ 性型分离群体, 利用分离群体分组分析法(Bulked Segregant Analysis, BSA) 构建全雌和弱雌两个基因池, 筛选了64对AFLP选择性引物EcoR I-NN +Mse I-NNN组合, 发现EcoR I-TG +Mse I-CAC引物组合在全雌基因池中扩增出一条分子量为234 bp的特异带。经F₂ 代单株验证, 该特异条带能在全雌单株中稳定出现。以MAP MAKER (Version 310) 软件分析, 该标记与全雌性位点的连锁距离在617 cM。命名该连锁标记为TG/CAC₂₃₄。将该特异条带回收、克隆、测序, 设计特异SCAR引物, 再对F₂ 代单株基因组DNA进行扩增, 仅在全雌单株中扩增出1条分子量为166 bp 的特异带, 表明已成功地将与黄瓜全雌性连锁的AFLP标记转化为操作简便、表现稳定的SCAR标记, 该标记命名为SA₁₆₆。

Identification of AFLP and SCAR Molecular Markers Linked to Gynoecious Loci in Cucumis sativus L.

Gynoecy plays an important role in cucumber (Cucumis sativus L. ) heterosis breeding and identification of the markers linked to this character will facilitate selection of gynoecious cucumber line in breeding p rogram. In the present study, selfed gynoecious cucumber‘Delta Star’and monoecious cucumber‘Beijing Jietou’were used as parents to make F₁ and then selfed to build F₂ sex segregated population. Gynoecious and monoecious DNA pools were developed separately using bulked segregant analysis (BSA). Amplified fragment length polymorphism (AFLP) technique with 64 primer combinations were emp loyed to find the polymorphisms between both DNA pools, and in gyneocious DNA pool a 234 bp specific fragment was amplified in the primer combination of TG +CAC. This marker was testified with individual DNA of the F₂ population and the band could only be amplified in the gynoecious plants. Linkage analysis using the software of MAPMAKER ( version 3.0) indicated its genetic distance to the gynoecious lociwas 617 cM, and this AFLP marker was designed as TG/CAC₂₃₄. This band was collected and sequenced to synthesize a sequence-characterized amplified region (SCAR) primer. The primer was used to amplify the individual DNAs of the F₂ population and obtained a specific band of 166 bp in the gynoecious plants, indicating a successful conversion of the SCAR marker from AFLP one. This SCAR markerwas designed as SA₁₆₆ , and has been practically useful to the marker-assisted selection in our cucumber breeding program.