桃蚜自然种群初级和次级共生菌的分子鉴定  

Molecular identification of the primary and secondary symbionts of the green peach aphid, Myzus persicae (Sulzer)

作　　者：李正西[1] 李定旭[1] 

机构地区：[1]中国农业大学昆虫学系,北京100094

出　　处：《昆虫学报》2005年第5期810-814,共5页Acta Entomologica Sinica

基　　金：中华人民共和国教育部留学回国人员科研启动基金项目(21163512)

摘　　要：蚜虫不仅带有专性初级内共生菌,还常常带有不同类群的兼性次级共生菌.本研究采用真细菌16S rDNA的通用引物,从桃蚜Myzus persicae(Sulzer)烟草种群体内扩增出1.5kb的共迁移目的条带,然后将其克隆,并在阳性克隆筛选时进行了RFLP分析.当采用EcoRⅠ进行单酶切分析时,目的片段被切割成～650 bp和～850 bp两个小片段;当采用EcoRⅠ和HindⅢ进行双酶切分析时,该蚜群共生菌酶切谱带被分成2组,其中1组(Group Ⅰ)只具有一个EcoRⅠ酶切位点,而另1组(GroupⅡ)不仅具有一个EcoRⅠ酶切位点,还具有一个HindⅢ酶切位点,而且Group Ⅰ为优势共生菌群.在此基础上分别对2组共生菌的16S rDNA全序列(～1.5kb)进行了测定,结果表明:GroupⅠ属于泛菌属Pantoea,与成团泛菌Pantoea agglomerans亲缘关系最近(同源性达99.70%),而GroupⅡ属于蚜虫的专性内共生菌,即Buchnera aphidicola(同源性达99.50%).这是在蚜虫体内存在泛菌次级共生菌的首次报道.Aphids harbor not only primary endosymbionts, namely Buchnera aphidicola, but also different secondary symbionts. A single comigrating DNA band of about 1.5 kb was amplified from a population of the green peach aphid, Myzus persicae （Sulzer） collected from the experimental fields in China Agricultural University （Beijing） using a pair of “universal” primers designed based on the full 16S rDNA of a wide range of eubacteria. This target DNA was then ligated to T-vector and cloned into E. coli DHSa. The clones were analyzed using restriction fragment length polymorphism （RFLP）. The results showed that EcoR Ⅰ cut the insert into two sub-fragments （ ～650 bp and ～850 bp） in all assayed samples, while double digestion with EcoR Ⅰ and Hind Ⅲ resulted in two different groups of RE （restriction enzyme） bands, with Group Ⅰ having only one EcoR Ⅰ site but Group Ⅱ having one EcoR Ⅰ site and one Hind Ⅲ site. Meanwhile, Group Ⅰ is dominant. Based on RE grouping, the full 16S rDNA representative sequences from different groups were sequenced, and the phylogenetic analysis demonstrated that Group Ⅰ belonged to Pantoea, closely related to P. agglomerans （homology： 99.70% ）, whereas Group Ⅱ was closely related to Buchnera aphidicola, the obligate symbiont of aphids （homology： 99.50% ）. This is the first report that Pantoea exists in aphids.

关 键 词：桃蚜 共生菌 BUCHNERA aphidicola 泛菌 分子鉴定 16S RDNA 

分 类 号：Q966[生物学—昆虫学]