瓶囊碘泡虫的重描述及其与洪湖碘泡虫分子标记的比较  

Redescription of Myxobolus ampullicapsulatus and comparison with molecular marker of M.honghuensis

作　　者：张潇艺 丁鹏 张城豪 孙荣华 杨承忠 柳阳 ZHANG Xiaoyi;DING Peng;ZHANG Chenghao;SUN Ronghua;YANG Chengzhong;LIU Yang(School of Marine Science and Engineering,Qingdao Agricultural University,Qingdao 266109,China;Chongqing Key Laboratory of Animal Biology,College of Life Sciences,Chongqing Normal University,Chongqing 401331,China)

机构地区：[1]青岛农业大学海洋科学与工程学院,山东青岛266109 [2]重庆师范大学生命科学学院,动物生物学重庆市重点实验室,重庆401331

出　　处：《水产学报》2024年第5期180-190,共11页Journal of Fisheries of China

基　　金：国家自然科学基金(32073012)。

摘　　要：为了完善瓶囊碘泡虫的分类学特征及厘清其与洪湖碘泡虫的分类关系,实验采用形态学、组织学和分子生物学方法对瓶囊碘泡虫进行了重描述,并与洪湖碘泡虫的分子标记进行了系统比较。结果显示,瓶囊碘泡虫寄生于异育银鲫的鳃,形成乳白色的圆形或椭圆形孢囊,直径为1.2~1.4 mm。成熟孢子壳面观呈梨形,前端较尖,后端钝圆,孢子长17.3~19.6μm,孢子宽7.4~9.9μm。两个极囊呈瓶状,大小不等。大极囊长6.4~9.7μm,大极囊宽2.1~3.3μm;小极囊长5.3~8.9μm,小极囊宽2.0~3.3μm。极丝圈数为8~11圈。组织学分析显示,瓶囊碘泡虫寄生于鳃小片间的上皮组织。BLAST分析显示,本研究获得的瓶囊碘泡虫的小亚基核糖体DNA(SSU rDNA)序列与GenBank中瓶囊碘泡虫序列的相似性为99.5%~99.8%(KC425223~KC425225、MH329620、JQ690361、JQ690373、KJ725082、MN227351、DQ339482)。系统发育分析表明,瓶囊碘泡虫与洪湖碘泡虫形成姐妹支。瓶囊碘泡虫与洪湖碘泡虫分子标记序列的比较结果显示,这两种碘泡虫的序列相似性为98.2%~98.8%,遗传距离为0.014~0.018,存在27个碱基差异。SSU rRNA二级结构分析显示,瓶囊碘泡虫和洪湖碘泡虫同一物种不同群体间的二级结构一致,两个物种间的二级结构存在明显差异,表明SSU rRNA二级结构可以作为鉴别瓶囊碘泡虫和洪湖碘泡虫的分子特征。本研究完善了瓶囊碘泡虫在异育银鲫鳃部的详细寄生部位,提出SSU rRNA二级结构可以作为有效鉴别瓶囊碘泡虫和洪湖碘泡虫的分子标记。To improve the taxonomic characteristics of Myxobolus ampullicapsulatus and clarify its relationship with of M.honghuensis,M.ampullicapsulatus was comprehensively redescribed by morphological,histological and molecular methods,and a systematic comparison was made with molecular marker of M.honghuensis.In the present study,M.ampullicapsulatus was characterized by round or oval,white plasmodia in gills of gibel carp Carassius auratus gibelio,measuring 1.2-1.4 mm in diameter.Myxospores were pear-shaped in front view with pointed anterior end and rounded posterior,measuring 17.3-19.6μm in length,7.4-9.9μm in width.Two ampullaceous polar capsules were unequal in size,with the larger polar capsule measuring 6.4-9.7μm×2.1-3.3μm and the smaller one 5.3-8.9μm×2.0-3.3μm.Polar filament coiled 8-11 turns.Histological analysis demonstrated that M.ampullicapsulatus developed within stratified epithelium between adjacent gill lamellae.A BLAST search conducted in this study revealed a high degree of similarity,ranging from 99.5%to 99.8%,between the obtained small subunit ribosomal DNA(SSU rDNA)sequence and those of M.ampullicapsulatus in GenBank(KC425223-KC425225,MH329620,JQ690361,JQ690373,KJ725082,MN227351,DQ339482).Furthermore,phylogenetic analysis indicated that M.ampullicapsulatus was closely related to M.honghuensis,serving as its sister species.Upon comparing the SSU rDNA sequences of M.ampullicapsulatus and M.honghuensis,it was observed that they shared a sequence similarity of 98.2%to 98.8%,a genetic distance of 0.014 to 0.018,and 27 base differences.The analysis of SSU rRNA sequences revealed that the secondary structures of different populations of M.ampullicapsulatus and M.honghuensis were found to be consistent,and there are obvious differences in the secondary structure between the two species.Moreover,notable differences were observed in the secondary structures of these two Myxobolus species,suggesting that the SSU rRNA secondary structure is expected to serve as a molecular feature to differentiate M.ampu

关 键 词：粘孢子虫 小亚基核糖体DNA(SSU rDNA) 二级结构 系统发育分析 

分 类 号：S941.5[农业科学—水产养殖]