BACKGROUND Insect pests belonging to genus Bactrocera sp. (Diptera: Tephritidae) pose major biotic stress on various fruits and vegetable crops around the world. Zeugodacus and Bactrocera sp. are associated with diverse bacterial communities which play an important role in the fitness of sterile insects. The wild populations of melon fly, Zeugodacus cucurbitae (Coquillett) and Oriental fruit fly, Bactrocera dorsalis (Hendel) were collected from pumpkin and mango fields, respectively. The laboratory populations of Z. cucurbitae and B. dorsalis were mass-reared on bottle gourd and sweet banana, respectively. Bacterial communities present in the gut of wild and mass-reared mature (~ 12 days old) and newly emerged (< 1 h after emergence) male and female adults of Z. cucurbitae and B. dorsalis were assessed. We used Illumina HiSeq next-generation sequencing of 16S rRNA gene to profile the gut bacterial communities of wild and mass-reared mature and newly emerged Z. cucurbitae and B. dorsalis adults. RESULTS We found diverse bacterial composition in the gut of wild and mass-reared Z. cucurbitae (ZC) and B. dorsalis (BD) with varied relative abundance. Few taxonomic groups were common to both the species. The most dominant phyla in all samples of Z. cucurbitae and B. dorsalis adults were Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The phylum Proteobacteria occurred more in wild Z. cucurbitae (~ 87.72%) and B. dorsalis (~ 83.87%) as compared to mass-reared Z. cucurbitae (64.15%) and B. dorsalis (~ 80.96%). Higher relative abundance of Phylum Firmicutes was observed in mass-reared fruit fly than wild adults. Cyanobacteria/Chloroplast and Actinobacteria were also present with very low relative abundance in both wild as well as mass-reared melon fly and Oriental fruit fly. Enterobacteriaceae (61.21%) was dominant family in the gut of both wild and mass-reared adults. Providencia and Lactococcus were dominant genera with varied relative abundance in wild as well as in mass-reared mature and newly emerged fruit fly adults of both species. Some of the genera like Morganella and Serratia were only detected in mass-reared mature and newly emerged Z. cucurbitae and B. dorsalis adults. Principal Coordinate Analysis (PCoA) showed that fruit fly adult samples were grouped based on species and age of the adults while no grouping was observed on the basis of sex of the adult fruit fly. CONCLUSIONS The gut bacterial communities associated with wild and mass-reared mature and newly emerged adults of Z. cucurbitae and B. dorsalis showed variation that depends on species and age of the insects. Understanding the gut microbiota of wild and mass-reared Z. cucurbitae and B. dorsalis using high throughput technology will help to illustrate microbial diversity and this information could be used to develop efficient mass-rearing protocols for successful implementation of sterile insect technique (SIT).

中文翻译：

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宏基因组测序揭示了野生和大量繁殖的葫芦科和背果小肠的肠道细菌群落。

背景技术属于Bactrocera sp。属的昆虫。（Diptera：Tephritidae）对世界各地的各种水果和蔬菜作物构成主要的生物胁迫。Zeugodacus和Bactrocera sp。它们与各种细菌群落有关，这些细菌群落在不育昆虫的适应性中起着重要作用。分别从南瓜田和芒果田收集了野生瓜蝇，葫芦科（Coquillett）和东方果蝇，桔小实蝇（Hendel）。在葫芦和甜香蕉上分别大量繁殖了葫芦科植物和桔小实蝇的实验室种群。评估了野生的和大量繁殖的成熟（〜12天大）和新出现（出苗后<1 h）肠道中的细菌群落。我们使用Illumina HiSeq 16S rRNA基因的下一代测序来分析野生的和大量繁殖的成熟和新近出现的葫芦科和桔小实蝇成虫的肠道细菌群落。结果我们在野生和大量饲养的葫芦科（ZC）和背果双歧杆菌（BD）的肠道中发现了不同的细菌组成，并且相对丰度也不同。这两个物种很少有分类群。在葫芦科Z.葫芦科和背部B. dorsalis的所有样品中，最主要的菌群是放线菌，拟杆菌，硬毛菌和变形杆菌。与大量繁殖的葫芦科的Z.（64.15％）和背果的B. dorsalis（〜80.96％）相比，野生的葫芦科的Z.（〜87.72％）和背果的B. dorsalis（Proteobacteria）发生率更高。在成批饲养的果蝇中，实蝇的相对丰度要比野生成虫高。蓝藻/叶绿体和放线菌在野生以及大量繁殖的瓜蝇和东方果蝇中的相对丰度也很低。肠杆菌科（61.21％）是野生和成年饲养成年人肠道中的主要家族。普罗维登西亚和乳球菌是优势种，在野生以及大量繁殖的成熟和新出现的两种果蝇成虫中，其相对丰度都不同。一些属，如Morganella和Serratia，仅在大量繁殖的成熟和新近出现的葫芦科植物Z. cucurbitae和B. dorsalis成年人中发现。主坐标分析（PCoA）显示，果蝇成年样品是根据成年的种类和年龄进行分组的，而未根据成年果蝇的性别进行分组。结论与葫芦科的Z. cucurbitae和背果的B. dorsalis的野生和大量繁殖的成熟和新近出现的成虫相关的肠道细菌群落显示出取决于昆虫的种类和年龄的变异。使用高通量技术了解野生和大量繁殖的葫芦科和桔小肠的肠道菌群将有助于说明微生物多样性，该信息可用于开发有效的大规模繁殖方案，以成功实施无菌昆虫技术（SIT） 。