中文摘要：

以大岩桐（Sinningia speciosa）花蕾RNA为模板,利用RACE技术克隆了大岩桐GAI同源基因的全长cDNA,命名为SsGAI（在GenBank中登录号为：FJ594773）.序列分析表明,SsGAI的ORF长度为1689bp,编码562个氨基酸,含有典型的植物DELLA结构域以及GRAS结构域.蛋白同源性分析表明,SsGAI与葡萄的VvGAI及陆地棉的GhGAI相似性分别为68%、64%.SsGAI基因在花萼中的相对表达量最高,在茎中表达沉默.将SsGAI置于CaMV35S启动子控制下在烟草中异位表达,转基因烟草表现出植株矮化,花瓣数增加,花期延迟等新表型,表明SsGAI参与了转基因烟草株高及花器官的发育.

英文摘要：

Taking the floral buds RNA of Sinningia speciosa ,the full-length cDNA of GA I homologous gene is cloned by rapid-amplification of cDNA ends （RACE） technology ,and named SsGA I .The SsGA I has an open reading frame （ORF） of 1689 bp length encoding 562 amino acids as well as the typical plant DELLA domain and GRAS domain .The protein homologous analysis indicates that SsGAI is similar to VvGAI（Vitis vinifera） and GhGAI（Gossypium hirsutum） with the similarity of 68% and 64% .SsGA I gene expressed highly in the sepals ,but is silence in the stem .Placing SsGA I under the control of CaMV35S promoter and ectopic expressing in tobaccos ,the transgenic tobacco plants exhibit novel phenotypes with dwarf plant ,increased petal number and late flowering .These results indicate that SsGA I is involved in the plant height and floral organ development of transgenic tobaccos .