Comparison of bacterial communities between midgut and midgut contents in two silkworms, Antheraea pernyi and Bombyx mori

Huan Wang,Xu-Wei Zhu,Tian-Mao Wang,Xiao-Meng Wang,Li Qin,Jing-Yu Zhang,Yan-Qun Liu,Hua-Lei Hu,Run-Xi Xia,Qun Li

doi:10.1038/s41598-020-69906-y

Abstract

Bacterial communities living inside the midgut of insects have been attracting increasing interest. Previous studies have shown that both the midgut and midgut contents harbor bacterial communities. However, whether the bacterial communities of the insect midgut are similar to those of the insect midgut contents (including the peritrophic membrane, food particles, and digestive fluids secreted by the midgut in this study) remains unknown. In the present study, we analyzed two economically important silkworms, the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae) and the mulberry silkworm Bombyx mori (Lepidoptera: Bombycidae), through Illumina MiSeq technology to address this issue. In A. pernyi larvae, 17 phyla and 162 genera were found in the midgut, while 7 phyla and 36 genera were found in the midgut contents. For B. mori larvae, 30 phyla and 465 genera were found in the midgut, but 22 phyla and 344 genera were found in the midgut contents. This evidence from the two silkworms suggests that the bacterial composition and diversity in the midgut are more diverse than those in the midgut contents. Principal component analysis revealed a significant difference in the bacterial community structure between the midgut and midgut contents of B. mori. To our knowledge, this is the first study to compare the bacterial communities between the midgut and midgut contents in insects, and the results will provide useful information for probing the functional differentiation within the midgut in the future.

Highlights

Bacterial communities living inside the midgut of insects have been attracting increasing interest
The richness rarefaction curves for individual samples began to plateau by the time all reads had been analyzed, indicating that the sequencing depth was sufficient to uncover most of the biodiversity in the larval intestine
The Shannon index was used to estimate the bacterial diversity, and the Shannon rarefaction curves tended to plateau, indicating that the bacterial diversity varied in different samples

Summary

Introduction

Bacterial communities living inside the midgut of insects have been attracting increasing interest. Principal component analysis revealed a significant difference in the bacterial community structure between the midgut and midgut contents of B. mori To our knowledge, this is the first study to compare the bacterial communities between the midgut and midgut contents in insects, and the results will provide useful information for probing the functional differentiation within the midgut in the future. We used two economically important silkworm species, the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae) and the mulberry silkworm Bombyx mori (Lepidoptera: Bombycidae), to comprehensively understand the intestinal bacterial communities of silkworms. Nutrient utilization, and silkworm diseases are directly linked to the gut bacterial community of silkworm larvae[20,21], information on the intestinal bacterial community will enhance our understanding of the diversity and function of silkworm intestinal microbiota

Objectives

Methods

Results

Conclusion