马氏珠母贝α-Tubulin基因结构、SNP筛选及耐低温相关性分析

α-Tubulin gene structure,SNP screening and its correlation with low temperature tolerance in the pearl oyster(Pinctada fucata martensii)

为了探究马氏珠母贝(Pinctada fucata martensii)α-Tubulin基因在低温适应性中的作用,通过RACE克隆技术获得马氏珠母贝α-Tubulin基因,分析了α-Tubulin基因在低温胁迫下的表达趋势,并筛选和比较了马氏珠母贝耐低温选育系(R)F3和北部湾野生群体(W)的α-Tubulin编码区SNP位点。结果表明:马氏珠母贝α-Tubulin基因总长为2107 bp,可编码454个氨基酸,具有典型的Tubulin和Tubulin-C结构域;全组织定量显示,α-Tubulin基因在所有组织中均有表达,在足部中表达量最高(P<0.05);低温胁迫时,鳃组织中α-Tubulin基因在低温组(12、17℃)的表达量均在72 h时达到最高,且显著高于对照组(22℃)(P<0.05);α-Tubulin外显子区域共有34个SNP,其中3个SNP位点的基因型频率在R和W群体间有显著性差异(P<0.05);连锁不平衡分析显示,R群体单倍型CCTCAGCGCC的频率明显高于W群体。研究表明,α-Tubulin为参与调节马氏珠母贝低温适应过程中的候选基因,筛选出的与抗低温性状相关的SNP位点g.111071125及优异单倍型CCTCAGCGCC,可作为选择育种的候选标记。

In order to explore the function ofα-Tubulin gene of the pearl oyster(Pinctada fucata martensii)in low temperature adaptability,ɑ-Tubulin gene of pearl oyster was identified in this study,the expression trend ofɑ-Tubulin was analyzed in response to low-temperature stress,and the SNP sites in theɑ-Tubulin coding region of pearl oyster were screened and compared between the low temperature resistan line(R)F3 and the Beibu Gulf wild population(W).The results showed thatα-Tubulin has a total length of 2107 bp,encoding a 454 amino acid protein containing typical Tubulin and Tubulin-C domains.Whole-tissue quantification showed thatɑ-Tubulin was expressed in all examined tissues,with the highest expression in the foot(P<0.05).Under low temperature stress,ɑ-Tubulin relative expression in gill in the low temperature group(12 and 17℃)reached the highest value at 72 h,which was significantly higher than that in the control group(22℃)(P<0.05).There were 34 SNP in theɑ-Tubulin exon region,and the genotype frequencies of 3 SNP were significantly different between the R and W populations(P<0.05).Linkage disequilibrium analysis showed that the frequency of haplotype CCTCAGCGCC in the R population was significantly higher than that in the W population.All data observed in this research show thatɑ-Tubulin might be a candidate gene involved in regulating the adaptation to low temperature of the pearl oyster.The SNP site g.111071125 and excellent haplotype CCTCAGCGCC related to low temperature resistance could be selected as candidate markers for selective breeding.