DNA条形码在海蜇食物组成鉴定中的应用

Application of DNA Barcoding in Analyzing Food Composition of Jellyfish Rhopilema esculentum

对海蜇的食性进行研究有助于查明其饵料来源及其在食物网中的功能地位,而全面准确地获取其食物种类信息是关键。由于传统镜检方法具有局限性,目前对海蜇具体的摄食种类和食物结构尚缺乏充分的了解。DNA条形码技术的发展给海蜇食性研究带来了机遇。笔者以线粒体COⅠ和ITS-5.8SrDNA这两种基因片段为DNA条形码标记,对辽东湾近海海蜇的现场食物组成进行分析,比较两种分子标记作为海蜇食性鉴定条形码的适用性和潜力,评估这两个DNA条形码用于检测海蜇食物组成的应用前景。研究结果显示:基于COⅠ基因通用引物扩增海蜇现场样品所构建的克隆文库共获取36个有效序列,来源于4个物种;而基于ITS-5.8SrDNA通用引物扩增共得到30个有效序列,来源于10个物种。利用DNA条形码技术能检测到鱼卵、仔稚鱼或成鱼碎屑、贝类浮游幼体等海蜇的潜在食物种类。研究结果表明,以传统测序为基础的DNA条形码技术由于测序通量低,在研究海蜇这一广食性种类的食物谱时可能具有较大的局限性。研究结果可为深入研究海蜇乃至水母的食物组成提供参考。

Feeding analysis of edible jellyfish Rhopilema esculentum is helpful to understand its food sources and functional role.Comprehensively and accurately obtaining the information on food species is critical for this endeavor.However,information about the feeding types and food structures of jellyfish remains obscure because of the limitations of traditional methods.Unrestricted to the morphology of prey,DNA barcoding based method could get more accurate results efficiently.DNA Barcoding is not only used in initially proposed simple species identification,but also in studies of animal diets,food chain,and food web by using short DNA fragments extracted from feces and intestinal contents of animals.In this study,DNA barcoding method was used to analyze the diet of jellyfish in Liaodong Bay coastal waters to make more comprehensive analysis towards its diet compositions.COⅠgene and ITS-5.8S rDNA were used as the target gene,and universal primers were designed to identify food composition of the jellyfish by DNA barcoding.A total of 36 effective COⅠgene sequences were obtained and 4 species were identified,while 10 species from 30 effective ITS-5.8S rDNA sequences were identified by traditional sequencing.The results showed that using DNA barcoding identified some potentially food compositions species of the jellyfish,such as fish eggs/larvae,and planktonic larvae of shellfish.Howerer,those main preys of plankton were not found in traditional Sanger Sequencing on the dietary analysis of the jellyfish yet,which means the deficiency of Sanger Sequencing in analyzing food composition research.The finding provides reference for further study of jellyfish feeding.