黄瓜全雌性基因连锁的AFLP和SCAR分子标记

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

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(BulkedSegregantAnalysis,BSA)构建全雌和弱雌两个基因池,筛选了64对AFLP选择性引物EcoRINN+MseINNN组合,发现EcoRITG+MseICAC引物组合在全雌基因池中扩增出一条分子量为234bp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MAPMAKER(Version3.0)软件分析,该标记与全雌性位点的连锁距离在6.7cM。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166bp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。

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 program. In the present study, selfed gynoecious cucumber‘Delta Star’and monoecious cucumber‘Beijing Jietou’were used as parents to make F_1 and then selfed to build F_2 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 employed 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 F_2 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 loci was 6.7 cM, and this AFLP marker was designed as TG/CAC_ 234 . 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 F_2 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 marker was designed as SA_ 166 , and has been practically useful to the marker-assisted selection in our cucumber breeding program.