Abstract
BackgroundThe bamboo weevil Cyrtotrachelus buqueti, which is considered a pest species, damages bamboo shoots via its piercing–sucking mode of feeding. C. buqueti is well known for its ability to transform bamboo shoot biomass into nutrients and energy for growth, development and reproduction with high specificity and efficacy of bioconversion. Woody bamboo is a perennial grass that is a potential feedstock for lignocellulosic biomass because of its high growth rate and lignocellulose content. To verify our hypothesis that C. buqueti efficiently degrades bamboo lignocellulose, we assessed the bamboo lignocellulose-degrading ability of this insect through RNA sequencing for identifying a potential route for utilisation of bamboo biomass.ResultsAnalysis of carbohydrate-active enzyme (CAZyme) family genes in the developmental transcriptome of C. buqueti revealed 1082 unigenes, including 55 glycoside hydrolases (GH) families containing 309 GHs, 51 glycosyltransferases (GT) families containing 329 GTs, 8 carbohydrate esterases (CE) families containing 174 CEs, 6 polysaccharide lyases (PL) families containing 11 PLs, 8 auxiliary activities (AA) families containing 131 enzymes with AAs and 17 carbohydrate-binding modules (CBM) families containing 128 CBMs. We used weighted gene co-expression network analysis to analyse developmental RNA sequencing data, and 19 unique modules were identified in the analysis. Of these modules, the expression of MEyellow module genes was unique and the module included numerous CAZyme family genes. CAZyme genes in this module were divided into two groups depending on whether gene expression was higher in the adult/larval stages or in the egg/pupal stages. Enzyme assays revealed that cellulase activity was highest in the midgut whereas lignin-degrading enzyme activity was highest in the hindgut, consistent with findings from intestinal gene expression studies. We also analysed the expression of CAZyme genes in the transcriptome of C. buqueti from two cities and found that several genes were also assigned to CAZyme families. The insect had genes and enzymes associated with lignocellulose degradation, the expression of which differed with developmental stage and intestinal region.ConclusionCyrtotrachelus buqueti exhibits lignocellulose degradation-related enzymes and genes, most notably CAZyme family genes. CAZyme family genes showed differences in expression at different developmental stages, with adults being more effective at cellulose degradation and larvae at lignin degradation, as well as at different regions of the intestine, with the midgut being more cellulolytic than the hindgut. This degradative system could be utilised for the bioconversion of bamboo lignocellulosic biomass.
Highlights
The bamboo weevil Cyrtotrachelus buqueti, which is considered a pest species, damages bamboo shoots via its piercing–sucking mode of feeding
The results indicated that 806 unigenes had multiple domains that were assigned to carbohydrate-active enzyme (CAZyme) families, including 55 glycoside hydrolases (GHs) families 309 GHs, 51 GT families 329 GTs, 8 carbohydrate esterases (CEs) families 174 CEs, 6 polysaccharide lyases (PLs) families 11 PLs, 8 auxiliary activities (AAs) families 131 enzymes with AAs and 17 carbohydrate-binding modules (CBMs) families 128 CBMs (Additional file 1: Table S1; Additional file 2: Table S2)
Using transcriptome analysis to dissect the mode-of-action of lignocellulose degradation in C. buqueti, this work provides a theoretical basis for the development of bamboo as a bioresource for the biofuel and bioenergy industries
Summary
The bamboo weevil Cyrtotrachelus buqueti, which is considered a pest species, damages bamboo shoots via its piercing–sucking mode of feeding. Lignocellulolytic activity was originally believed to be restricted to plants, bacteria and fungi, evidence has accumulated in recent years for the existence of animal lignocellulolytic enzyme activity (such as cellulases, hemicellulases and lignases), in cellulose-feeding insects [4,5,6,7]. These natural biomass utilisation systems (NBUS) are environmentfriendly and cost-effective for lignocellulose degradation, and their underlying mechanism could provide the basis for high-efficiency bioconversion of lignocellulose [8]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.