牙鲆(Paralichthys olivaceus)丝氨酸蛋白酶Ⅰ-1基因多态性

采用重测序方法，利用牙鲆(Paralichthys olivaceus)野生个体，扩增了牙鲆丝氨酸蛋白酶(Serine protease) I-1基因的编码区(CDS)和2605 bp的启动子序列。在牙鲆丝氨酸蛋白酶I-1基因(PoSP I-1)编码区中筛选出9个单核苷酸多态性位点(SNPs)，同时在其启动子区筛选出28个SNP位点。对感染鳗弧菌的抗病牙鲆和易感牙鲆进行了部分SNP位点的分型，通过分析CDS中SNP位点的分布情况，发现SNP365A/G位点在抗病个体中的AG基因型的基因频率是60%，高于易感个体的40% (P=0.01)。qRT-PCR结果显示，易感个体在细菌感染后，PoSP I-1相对表达量相比对照组呈下降趋势。在抗病个体中，PoSP I-1相对表达量相比对照组呈上升趋势，且高于易感个体。结果表明，丝氨酸蛋白酶基因在牙鲆抗鳗弧菌感染中发挥重要作用，该基因的SNP365A/G位点是与牙鲆鳗弧菌感染相关的候选位点，该位点可作为牙鲆抗鳗弧菌选择育种的潜在标记。

The Polymorphism of Serine Protease I-1 in Japanese Flounder (Paralichthys olivaceus)

Serine proteases are enzymes that have serine, histidine and aspartic acid in their active domain and same catalytic mechanisms, which play important roles in many diseases and intracellular signal transduction. In this study, we amplified the coding sequence and promoter sequence (2605 bp) of serine protease I-1 from Japanese flounder Paralichthys olivaceus (PoSP I-1). We identified 9 single nucleotide polymorphisms (SNPs) and 28 SNPs in the coding sequence and promoter sequence of PoSP I-1, respectively. The analysis of all SNPs indicated that the frequency of SNP365A/G in the coding sequence of PoSP I-1 is significantly different between the resistant group (60%) and the susceptible group (40%) (P=0.01). Vibrio anguillarum injection reduced the expression of PoSP I-1 in the susceptible individuals but induced its expression in the resistant individuals. Moreover, PoSP I-1 in the resistant individuals is higher than that in the susceptible individuals. These results implied that PoSP I-1 is involved in the resistance of Japanese flounder to V. anguillarum. 365A/G of PoSP I-1 is a potential marker associated with the resistant Japanese flounders. In conclusion, PoSP I-1 365A/G is a candidate marker that could apply to disease resistant selective-breeding of Japanese flounder in the future.