不同性别表型黄瓜基因组中雌性系特异的ACC合酶基因

Studies on a Gynoecious-specific ACC Synthase Gene in Different Sexual Phenotypes of Cucumber Genome

利用一对引物 (引物 1和引物 2 )分别从雌性系黄瓜 (CucumissativusL .)品种“CORONA”、“DALEVE”和强雌性黄瓜品种“中农五号”、“欧洲八号”的基因组DNA中扩增到一长约 10 2 5bp的ACC合酶基因片段。序列分析表明 :该基因片段与Trebitsh等 1997年发表的ACC合酶基因片段的同源性大于 99% ,认为这两个基因片段应该是同一个基因 ,不同品种来源的该基因的相同性说明了其高度的保守性 ,并暗示了该基因在黄瓜性别决定中的重要作用。此基因片段与其他在不同诱导条件下表达的ACC合酶基因的同源性较低 (小于 70 % )。Southern分析表明此基因片段与黄瓜的性别表型有关 ,是雌性系黄瓜特有的。此基因的存在与黄瓜的雌性表达为“有”和“无”的关系 ,其拷贝数的多少与雌性表达强弱并无直接相关性 ,暗示在黄瓜中另有与雌性表达强弱有关的基因。

Using a pair of primers (Primer Ⅰ and Primer Ⅱ), the authors have amplified a fragment of ACC synthase gene about 1?025 bp from four varieties of gynoecious species of cucumber ( Cucumis sativus L.) viz.:“CORONA”,“DALEVE”,“Zhongnong No.5”,and “Ouzhou No.8”. Sequence analysis revealed that this fragment of ACC synthase gene was more than 99% homologous with the gene reported by Trebitsh et al (1997). The authors regard them as the same gene, but it exhibited less homology with this ACC synthase gene when expressed by other induction. Southern blot analysis showed that this fragment of ACC synthase gene is associated with the sexual phenotype of cucumber,and it is the specific gene of gynoecium. However, the number of its copies has no direct correlation with the degree of female expression; this seems to indicate that there might be other genes associated with the degree of feminization.