Institute of Sericulture and Apiculture, College of Animal Sciences, Zhejiang University, Hangzhou, China.
Analysis Center of Agrobiology and Environmental Sciences, Zhejiang University, Hangzhou, China.
ISME J. 2018 Sep;12(9):2252-2262. doi: 10.1038/s41396-018-0174-1. Epub 2018 Jun 12.
Bombyx mori, the domesticated silkworm, is of great importance as a silk producer and as a powerful experimental model for the basic and applied research. Similar to other animals, abundant microorganisms live inside the silkworm gut; however, surprisingly, the microbiota of this model insect has not been well characterized to date. Here, we comprehensively characterized the gut microbiota of the domesticated silkworm and its wild relatives. Comparative analyses with the mulberry-feeding moths Acronicta major and Diaphania pyloalis revealed a highly diverse but distinctive silkworm gut microbiota despite thousands of years of domestication, and stage-specific signatures in both total (DNA-based) and active (RNA-based) bacterial populations, dominated by the phyla Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Most fungal sequences were assigned to the phyla Ascomycota and Basidiomycota. Environmental factors, including diet and human manipulation (egg production), likely influence the silkworm gut composition. Despite a lack of spatial variation along the gut, microbial community shifts were apparent between early instars and late instars, in concert with host developmental changes. Our results demonstrate that the gut microbiota of silkworms assembles into increasingly identical community throughout development, which differs greatly from those of other mulberry-feeding lepidopterans from the same niche, highlighting host-specific effects on microbial associations and the potential roles these communities play in host biology.
家蚕是一种重要的经济昆虫，不仅可以生产蚕丝，而且还是基础和应用研究的有力实验模型。与其他动物一样，大量的微生物生活在家蚕的肠道内；然而，令人惊讶的是，这种模式昆虫的微生物群尚未得到很好的描述。在这里，我们全面描述了家蚕及其野生亲缘种的肠道微生物群。与桑蚕蛾 Acronicta major 和 Diaphania pyloalis 的比较分析表明，尽管经过数千年的驯化，家蚕肠道微生物群仍然具有高度的多样性和独特性，并且在总（基于 DNA）和活性（基于 RNA）细菌种群中都存在特定的阶段特征，主要由门变形菌门、厚壁菌门、放线菌门和拟杆菌门组成。大多数真菌序列被分配到子囊菌门和担子菌门。环境因素，包括饮食和人类干预（产卵），可能会影响家蚕的肠道组成。尽管肠道内没有明显的空间变化，但在早期和晚期幼虫之间，微生物群落发生了明显的变化，与宿主的发育变化一致。我们的结果表明，家蚕肠道微生物群在整个发育过程中逐渐形成越来越一致的群落，这与来自同一生态位的其他桑蚕蛾类完全不同，突出了宿主对微生物群的特定影响以及这些群落在家蚕生物学中的潜在作用。
