Metabolic and immunological effects of gut microbiota in leaf beetles at the local and systemic levels

Abstract

Insects' intestinal microbes have profound effects on the host's physiological traits, which can impact their physiology at both the local (gut) and systemic (body) levels. Nevertheless, the molecular mechanisms underlying hostmicrobiota interactions, especially in non-model insects, remain elusive. Recently, tissue-specific transcriptomic analysis has been highlighted as a robust tool in studying host-microbe interactions. Plagiodera versicolora is a worldwide leaf-eating pest that primarily feeds on willows and poplar. The interplay between gut microflora and this host beetle has yet to be studied. Herein, we investigate the effects of the gut microbiota on the body mass of P. versicolora larvae, compare the nutrition status of larvae in absence and presence of gut microbiota, and profile gut bacterial loads throughout its developmental larval stages. We then perform comparative transcriptomic analysis of gut and body tissues in axenic and non-axenic larvae. Finally, we confirm the expression patterns of representative genes in nutritional metabolism and immunity. Results show that weight growth is retarded in conventional larvae, with a concomitant increase of total bacterial load by the 5 th development day, and germ-free larvae have a higher glucose content than conventional-reared larvae. Both nutritional and immunological analyses indicate that gut bacteria are a burden in the beetle's larval development. These findings elucidate the impacts of gut microbiota on P. versicolora, and provide insight into tissue-specific responses to gut microflora in this pest at the genetic level, boosting our understanding of the molecular mechanisms underlying host-microbe interactions in leaf beetles and beyond.

Gastrointestinal Tract and Dietary Fiber Driven Alterations of Gut Microbiota and Metabolites in Durco × Bamei Crossbred Pigs

“…However, a high-DF diet can indirectly influence the digestibility of energy, amino acids, and other nutrition (19). As most of these small metabolites are closely related to host health and growth performance (10,18,20), determining the variation in microbial metabolites across different graded levels of DF diets could add to the available information for improving animal health and production. Liquid chromatography-mass spectrometry (LC-MS) is a popular tool for metabolomics analyses to determine the non-targeted profiles of a vast number of small metabolites.…”

Intestinal microbiota in various animals

“…To promote integrative studies on this topic among scientists of different disciplines and exchange scientific research work of different species, Integrative Zoology published a special subsection on Intestinal microbiome in animals in May 2021. Authors shared their progress not only in vertebrates including Indo-Pacific humpback dolphin Sousa chinensis (Wan et al 2021), whales (Globicephala macrorhynchus and Kogia breviceps) (Bai et al 2021) and forest musk deer Moschus berezovskii (Li et al 2021) but also in invertebrate such as a willow leaf beetle Plagiodera versicolora (Ma et al 2021). The results showed that gut microbial communities varied in different species, anatomical regions, life stages, seasons, and environments.…”

Bacillus cereus (EG-Q3) in the Gut of Ectropis grisescens Contributes to Host Response to Starvation Conditions

“…The gut microbiota is associated with many essential host physiological functions ( Sommer and Bäckhed, 2013 ; Xu et al, 2019 ; Grenier and Leulier, 2020 ). With the advent of sequencing technology, many bacteria impacting insect life activities have been found in the guts of a variety of insects ( Dillon et al, 2008 ; Hu et al, 2013 ; Fang et al, 2013 ; Ma et al, 2021 ). Some studies have focused on how insects adapt to different types of stress through gut microbes.…”