中文摘要：

利用分子克隆技术从8个水稻品种中克隆到谷氨酸脱羧酶基因仉O3GAD3，并进行了相关的生物信息学及表达谱分析．结果表明，不同水稻品种O3GAD3的核苷酸序列差异性很小，都在l％以内，在氨基酸序列上都具有保守的结构域，在C末端均具有类似于OsGADl结合CaM的关键氨基酸位点，但不同于0sGAD2．系统进化树分析表明，不同水稻品种的OsGAD3在进化上可以分为粳稻和籼稻两大类，与水稻常规分类相一致．此外，对不同水稻品种的谷氨酸脱羧酶基因的表达谱分析发现，O3GADl、O3GAD2、O3GAD3、O3GAD4、和O3GAD5在测试的11种水稻叶片中都有表达，但表达特征存在一定的差异性，可能与品种特性相关．

英文摘要：

In this study, glutamate decarboxylase genes （OsGAD3s） were successfully isolated from 8 rice varieties by using molecu lar cloning techniques, then related bioinformatics and expression profiles were also analyzed. The results showed that there is low nucleotide sequence differentiation of less than 1% among OsGAD3s from different rice varieties. The OsGAD3s all contain CaM binding key amino acid sites on the C terminal, which is similar to OsGAD1 but rather than OsGAD2. Phylogenic tree analysis indi cated that different OsGAD3s can be divided into two subgroups of japonica and indica, which is consistent with conventional classi fication of rice. In addition, expression profile analysis indicated that OsGADI, OsGAD2, OsGAD3, OsGA1M and OsGAD5 were all expressed in the tested rice varieties with different levels, which may be associated with the varieties difference. The cloning and a nalysis of OsGADs in different rice varieties will lay a good foundation for further understanding of physiological roles of different GADs and breeding novel rice varieties rich in γ-aminobutyric acid （GABA） by metabolic engineering in the future.