基于16S rDNA序列对蓖麻蚕肠道细菌多样性的研究

Diversity Analysis of Intestinal Bacteria in Philosamia cynthia ricini Based on 16S rDNA Sequence

蓖麻蚕(Philosamia cynthia ricini)是一种无滞育多化性、广食性、完全变态的吐丝昆虫,研究蓖麻蚕肠道菌群结构及多样性对了解其广食性分子基础具有十分重要的意义。选用蓖麻蚕品种B7,按蛾区半分法收蚁,分别喂食蓖麻叶和臭椿叶至5龄盛食期,提取肠道细菌总DNA,对16S rDNA的V3+V4区进行高通量测序,分析不同饲料喂食对蓖麻蚕的肠道微生物的OTU(operational taxonomic units)数量、组成、相似性、以及α和β多样性的影响。结果发现,蓖麻叶育和臭椿叶育的蓖麻蚕肠道优势菌表现相似,均以肠球菌(Enterococcus)、克雷伯氏菌(Klebsiella)、拟杆菌(Bacteroides)、葡萄球菌(Staphylococcus)为优势菌,但其所占比率有所不同;臭椿叶喂食的蓖麻蚕肠道内还检测到棒杆菌(Corynebacterium_1)、梭菌(Clostridium_sensu_stricto_3)、沙雷氏菌(Serratia)、梭状芽胞杆菌(Clostridium_sensu_stricto_12)、发光杆菌(Photobacterium)等菌属,其物种的多样性和丰富度比蓖麻叶喂食的蓖麻蚕更高。结果表明蓖麻蚕肠道内菌群结构和组成与其食性存在一定的关系,这可为研究家蚕的饲料使用方式、利用率及广食性家蚕品系筛选培育等提供借鉴。

Philosamia cynthia ricini is a non-diapause multivoltine,polyphagous and completely metamorphic silkspinning insect.It is very important to study the structure and diversity of intestinal flora for understanding the molecular basis of polyphagy.In this study,eri-silkworms of B7strain fed on castor leaf and Ailanthus altissima leaf from the ant to the 5th instar were used to extract total bacterial DNA of the intestinal tract.The V3+V4 region of the 16S rDNA was sequenced by using next-generation sequencing method to analyze the effects of different feeds on OUT (operational taxonomic units)quantity,composition,similarity,alpha and beta diversity of intestinal microbes.The results showed that Enterococcus,Klebsiella,Bacteroides and Staphylococcus exhibited common dominant floras in the intestines either fed on castor leaf or Ailanthus altissima leaf,but their proportions are different.Corynebacterium_l,Clostridium_sensu_stricto 3,Serratia,Clostridium_sensu_stricto_12 and Photobacterium were also detected in the gut of B7 fed on Ailanthus altissima leaf,suggesting that the diversity and richness of species is higher than that fed on castor leaf. The results showed that the structure and composition of the intestinal flora of the eri-silkworm may have a certain relationship with its special diet.It is also expected to provide useful information for the research on feed selection,utilization rate and breeding of polyphagous silkworm strains.