三角帆蚌GPX基因结构特征及抗性相关SNP的筛选  

Identification of genomic structure and resistance trait associated SNP loci in glutathione peroxidase gene of Hyriopsis cumingii

作　　者：李西雷[1] 汪桂玲[1] 李家乐[1,2] 

机构地区：[1]上海海洋大学,农业部淡水水产种质资源重点实验室,上海201306 [2]上海市高校水产养殖学E研究院,上海201306

出　　处：《遗传》2012年第11期1456-1464,共9页Hereditas（Beijing)

基　　金：国家自然科学基金项目(编号:31101939);上海市教委科研创新重点项目(编号:1322128);上海市科委基础研究重点项目(编号:10JC1406300)资助

摘　　要：根据三角帆蚌(Hyriopsis cumingii)谷胱甘肽过氧化物酶(Glutathione peroxidase,GPX)基因cDNA序列,通过PCR和基因组步移法,从三角帆蚌基因组DNA中扩增出GPX基因全长及其5′调控区。序列分析表明,该基因序列全长6 708 bp,含有2个外显子,1个内含子。5′调控区为992 bp,含有启动子的核心序列TATA盒以及其他一些转录调控元件,如AP1、C/EBP、CdxA。2个外显子长度分别为273 bp和991 bp,内含子长度为4 491 bp。通过直接测序法在三角帆蚌抗性群体和易感群体中筛选GPX基因的SNPs,并研究这些多态性位点与抗逆性状的相关性。共获得了16个SNP位点,其中启动子区的A-99G位点、A-86C位点、A-49C位点,内含子区的A2841T位点、C2847T位点、G3146C位点、A3150G位点以及G4645T位点共8个SNP位点的基因型频率和等位基因频率在抗性和易感群体中均存在显著性差异(P<0.05)。连锁不平衡分析结果显示GPX基因A-86C位点、A-49C位点、C2847T位点、A3150G位点与G4645T位点之间,以及A2841T位点与G3146C位点之间均存在强连锁不平衡。同时单倍型分析发现,在抗性群体中单倍型分别为ACTGT和TG的个体出现的频率显著高于易感群体中出现的频率。这些结果表明,GPX基因的部分SNPs可作为三角帆蚌抗病辅助育种的候选分子标记。Based on the eDNA sequence of GPX in Hyriopsis cumingii, the complete genomic DNA of GPX gene and it＇s 5＇-flanking region were identified from H. cumingii using PCR and genome walking technique. The length of the com- plete genomic sequence was 6 708 bp including the 5＇-flanking region, two exons, and one intron. Sequence analysis of the 992 bp 5＇-fianking region revealed that it contained a core promoter element （TATA-box） and other transcription regulation elements such as AP1, C/EBP, and CdxA. The sequence lengths of the two exons were 273 bp and 991 bp, respectively, and the intron was 4 491 bp in length. Sixteen single nucleotide polymorphisms （SNPs） were detected in the GPXgene from resistant stock （RS） and susceptible stock （SS） of H. cumingii. These polymorphisms were analyzed with regard to resis- tance to Aeromonas hydrophila. Among them, three SNPs including A-99G, A-86C, and A-49C in GPXpromoter and five SNPs including A2841T, C2847T, G3146C, A3150G, and G4645T in GPX introns were associated with resis- tance/susceptibility ofH. cumingii to A. hydrophila, both in genotype and allele frequency. Linkage disequilibrium analysis revealed that A-86C, A-49C, C2847T, A3150G; G4645T, A2841T, and G3146C were in high linkage disequilibrium, and haplotype analysis revealed that the frequency of two major predominant haplotypes （ACTGT and TG） in the resistant group was significantly higher than that in the susceptible group. The results suggest that the polymorphic loci in the GPX gene could be potential genetic markers for future molecular selection of strains resistant to diseases.

关 键 词：三角帆蚌 GPX基因 SNP 抗性性状 

分 类 号：S917.4[农业科学—水产科学]