摘 要 ：SGT1(suppressor of the G2 allele of skp1)是多种植物抗病基因介导的抗病信号途径中的重要元件。该研究利用RT-PCR和RACE方法克隆出甘薯近缘野生种三浅裂野牵牛的SGT1基因,命名为ItSGT1。该基因含有一个长度为1 087 bp的开放阅读框,编码361个氨基酸,分子量约为40.1 kD,等电点为5.05。Blast及多序列比对分析表明,该基因与其他植物中的SGT1具有较高的相似性,且具有SGTl蛋白典型的功能域结构,即TPR区、VR1区、CS区、VR2区和SGS区。Southern杂交结果显示,SGT1基因在三浅裂野牵牛基因组中是多拷贝基因。组织特异性表达分析表明,ItSGT1基因在三浅裂野牵牛的根、茎和叶中均有表达。
Abstract:SGTl (suppressor of the G2 allele of skp1) is a required component in some signaling pathways mediated by disease resistance (R) genes in many plant species.In this study,a full-length cDNA encoding the SGT1 protein was isolated from Ipomoea trifida by RT-PCR and RACE,designated ItSGT1.ItSGT1 has an open reading frame of 1 087 bp encoding putative protein of 361 amino acid residues.The molecular weight of putative protein is 40.1 kD and its pI is 5.05.The predicted SGT1 protein contained typical SGT1 domains of TPR,VR1,CS,VR2 and SGS.The deduced amino acid of ItSGT1 showed higher degree of similarities with their orthologs in other plant species.Southern blot analyses revealed that SGT1 was a multi-copy gene in the I.trifida genome.Analysis of ItSGT1 expression at the mRNA level by semi-quantity RT-PCR showed that ItSGT1 was expressed in different tissues.