Diversity and functional analysis of Chinese bumblebee gut microbiota reveal the metabolic niche and antibiotic resistance variation of Gilliamella

Abstract

Bumblebees play an important role in maintaining the balance of natural and agricultural ecosystems, and the characteristic gut microbiota of bumblebees exhibit significant mutualistic functions. China has the highest diversity of bumblebees; however, gut microbiota of Chinese bumblebees have mostly been investigated through cultureindependent studies. Here, we analyzed the gut communities of bumblebees from Sichuan, Yunnan, and Shaanxi provinces in China through 16S ribosomal RNA amplicon sequencing and bacterial isolation. It revealed that the bumblebees examined in this study harbored two gut enterotypes as previously reported: one is dominated by Gilliamella and Snodgrassella, and the other is distinguished by prevalent environmental species. The gut compositions obviously varied among different individual bees. We then isolated 325 bacterial strains and the comparative genomic analysis of Gilliamella strains revealed that galactose and pectin digestion pathways were conserved in strains from bumblebees, while genes for the utilization of arabinose, mannose, xylose, and rhamnose were mostly lost. Only two strains from the Chinese bumblebees possess the multidrug-resistant gene emrB, which is phylogenetically closely related to that from the symbionts of soil entomopathogenic nematode. In contrast, tetracycline-resistant genes were uniquely present in three strains from the USA. Our results illustrate the prevalence of strain-level variations in the metabolic potentials and the distributions of antibiotic-resistant genes in Chinese bumblebee gut bacteria.

Gut Microbiota Dysbiosis Influences Metabolic Homeostasis in Spodoptera frugiperda

“…In particular, we found that cytochrome c oxidase subunit 6A (gene-LOC118269158) and UDP-glucuronosyltransferase 2C1 (gene-LOC118277905) were significantly upregulated. Our results were consistent with the results in S. litura and Chinese bumblebee that gut microbiota affected the energy and carbohydrate metabolism after antibiotics exposure ( Thakur et al, 2016 ; Zhang et al, 2021 ). Meanwhile, the triacylglycerol lipase gene and glutathione S-transferase (GST) were upregulated ( Figure 6 ).…”

“…Gut microbial community is often influenced by weather, temperature, diet, and other environmental factors such as antibiotics ( Schoeler and Caesar, 2019 ; Zhang et al, 2020 ). In social insects like the honeybee ( Apis mellifera ), the dysbiosis of gut microbial community caused by antibiotic exposure affects bee health and elevates mortality, in part due to increased susceptibility to pathogens ( Powell et al, 2014 ; Raymann et al, 2017 ), whereas in the Chinese bumblebees (genus Bombus comprising eight species in Zhang’s paper), antibiotics can cause changes of the sugar metabolism and distributions of antibiotic-resistant genes in main bacterial symbiont Gilliamella ( Zhang et al, 2021 ). In the gypsy moth Lymantria dispar (Lepidoptera: Lymantriidae), gut microbiota in the larval stage eliminated by antibiotics exposure abolished Bacillus thuringiensis insecticidal activity and influenced the immune responses ( Broderick et al, 2006 ).…”

Interkingdom Gut Microbiome and Resistome of the Cockroach Blattella germanica

“…Those genes confer resistance against antibiotics used in clinics, agriculture, and farming, such as beta-lactams, folate synthesis inhibitors, tetracyclines, amphenicols, glycopeptides, polymyxins, or aminoglycosides. Reservoirs of ARGs have also been identified in other gut microbiomes and environmental metagenomes ( 52 , 54 , 70 , 71 ). A notable result in our model is the significant increase in the relative abundance of ARGs after different antibiotic treatments, generating profiles associated with the antibiotic type used ( Fig.…”

The Microbiome of the Medicinal Plants Achillea millefolium L. and Hamamelis virginiana L.

“…The flower-exclusive core community comprised primarily Lactobacillales and Enterobacteriaceae and some of them were exclusive to the epi- or endophytic compartment indicating their very specific adaptation to these habitats rich in easily degradable carbohydrates. One mode of transmission of the flower-associated taxa certainly was insect pollination as indicated by the flower-specific epiphytic Gilliamella , well known from the gut of bees, hornets and bumble bees ( Moran, 2015 ; Graystock et al, 2017 ; Suenami et al, 2019 ; Zhang et al, 2020 ). Interestingly, we also detected Gilliamella on leaves of Hamamelis and on leaves of Achillea in spring, assuming a transmission by insect feces or resting insects, as both plants did not flower at this time.…”