GC/TOF-MS-Based Metabolomics Reveals Altered Metabolic Profiles in Wood-Feeding Termite Coptotermes formosanus Shiraki Digesting the Weed Mikania micrantha Kunth.

Wenjing Wu,Zhiqiang Li,Yong Chen,Shijun Zhang,Yahui Hou,Wenhui Zeng

doi:10.3390/insects12100927

Wenjing Wu, Zhiqiang Li + Show 4 more

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https://doi.org/10.3390/insects12100927

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Abstract

Simple SummaryMikania micrantha Kunth is among the most invasive weeds in the world, causing extensive damage to both natural ecosystems and agroforestry systems. Mechanical removal is one of the most effective and straightforward approaches to controlling this weed, but this results in extensive lignocellulosic waste, and effective approaches to exploiting this abundant biomass are limited. Coptotermes formosanus Shiraki is not only an important subterranean termite pest species but also a considerable decomposer with the ability to digest lignocellulose. In this study, we evaluated the effects of a diet composed of M. micrantha leaves on C. formosanus workers. The workers increased their dietary intake when fed M. micrantha leaves, with a concomitant gradual increase in mortality rate. From the metabolic profiles, changes in metabolites and their related metabolic pathways suggested that termites can utilize M. micrantha-derived lignocellulose, but their antioxidant activity and signal transduction may be suppressed. Overall, this study identified key metabolites and pathways associated with the response of these termites to dietary changes and the effect of M. micrantha on termites.Effective approaches to exploiting the biomass of the abundant invasive weed Mikania micrantha Kunth are limited. Termites have been a focus of significant attention as mediators of biomass-processing owing to their ability to digest lignocellulose. Here, the GC/TOF-MS approach was employed to assess the effects of a diet composed of M. micrantha leaves on Coptotermes formosanus workers, with the growth performance of these workers also being assessed. The workers increased their dietary intake when fed M. micrantha leaves, with a concomitant gradual increase in mortality rate. A total of 62 differentially abundant metabolites and nine significantly affected pathways were found when comparing termites fed M. micrantha leaves to pinewood. Key metabolites, including carbohydrates, polyols, 4-hydroxyphenylacetic acid, and their related metabolic pathways, suggested that termites can digest and utilize M. micrantha-derived lignocellulose. However, changes in the tryptophan metabolism, tyrosine metabolism, and sphingolipid metabolism suggest an adverse effect of M. micrantha leaves on antioxidant activity and signal transduction in termites. Overall, this study identified the key metabolites and pathways associated with the response of these termites to dietary changes and the effect of M. micrantha on termites.

Highlights

Owing to their ability to decompose lignocellulose, termites are among the most ecologically important invertebrate detritivore species in the world [1]
Termites are commonly studied as a model organism by researchers evaluating the ability of species to adapt to specific forms of plant biomass degradation and to study the mechanisms of lignocellulose degradation
We began by assessing termite survival and dietary mass consumed for C. formosanus workers fed a M. micrantha leaves (ML) or pinewood (PW) diet

Summary

Introduction

Owing to their ability to decompose lignocellulose, termites are among the most ecologically important invertebrate detritivore species in the world [1]. Enzymatic activity in the guts of termites and associated symbiotic enzymatic activity, including endoglucanase, exoglucanase, xylosidase and glutathione peroxidase, has been shown to change in response to different diets composed of pinewood, corn stover, or soybean residue [6,7] These dietary changes are associated with shifts in the community richness and diversity of protists and bacteria within the gut microbiome of these termites, resulting in altered functional roles that facilitate optimal resource utilization [8,9,10,11,12,13]. The biochemical metabolites associated with these dietary and regulatory shifts, in contrast, have not been well-characterized to date

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