玉米ZmGS5基因克隆、分子特性分析及对拟南芥的遗传转化

高产是玉米育种的重要目标,籽粒大小是决定籽粒产量的重要因子。基于水稻中控制籽粒大小的OsGS5基因编码序列,利用同源克隆方法,获得了玉米ZmGS5基因,其cDNA全长为1 695bp,开放阅读框1 491bp,编码496个氨基酸,含有Peptidase-S10结构域、1个信号肽和1个丝氨酸羧肽酶（serine carboxypeptidases,SCP）类蛋白所特有的催化活性中心,这些都与SCP家族结构特点相符,也与OsGS5相关研究结果相同;磷酸化位点分析结果表明,ZmGS5含有丝氨酸、苏氨酸和酪氨酸等蛋白激酶识别位点。qRT-PCR分析显示ZmGS5在雄穗和叶片中的表达量较高,而在胚及胚乳中的表达量相对较低。除此之外,采用农杆菌介导法,建立了拟南芥的遗传转化体系,得到纯合转基因株系,T₃代转基因拟南芥种子千粒重为0.0169g,较野生型千粒重（0.0139g）高。

Cloning,Molecular Characteristics Analysis and Genetic Transformation of Arabidopsis thaliana of ZmGS5 Gene in Maize

High yield is an important goal of the maize breeding,grain size is a major determinative factor of high yield.In this study,based on the method of homology cloning,the OsGS5 sequence was used as a template to obtain the ZmGS5 gene.The sequencing result revealed that the full length cDNA of ZmGS5 was 1695bp.The Open Reading Frame(ORF)encoding 496 amino acid was 1491bp.The ZmGS5 protein contained conservative structure domain Peptidase-S10,a signal peptide,an active site of the serine carboxypeptidases,which were all conformed to the structure of serine carboxypeptidase family and also conformed to the OsGS5 related research results.Phosphorylation locus analysis indicated that the protein contained recognition loci of Ser,Thr,Tyr kinases.The result of real-time quantitative PCR showed that ZmGS5 had a much higher expression level in tassel and leaves,and the lower expression level in embryo and endosperm.According to agrobacterium-mediated method,we established genetic transformation system in Arabidopsis and obtained homozygous transgenic lines.The 1000-seed weight of T3 Arabidopsis(0.0169g)was higher than that of wild type(0.0139g).