Lignin-associated metagene expression in a lignocellulose-digesting termite

Sethi, Amit; Slack, Jeffrey M.; Kovaleva, E. S.; Buchman, George W.; Scharf, Michael E.

doi:10.1016/j.ibmb.2012.10.001

Cited by 69 publications

(120 citation statements)

References 41 publications

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“…In addition to laccases, 26 unigenes predicted to encode aldo-keto reductases were detected in the A. glabripennis transcriptome. In a recent study, expression levels of termite-produced aldo-keto reductases were correlated with feeding on wood and a recombinant aldo-keto reductase expressed in conjunction with other termite-derived cellulases enhanced sugar release from pine saw dust [52], suggesting a role in enhancing lignocellulose digestion. Additionally, aldo-keto reductases have been shown to enhance xylose metabolism [53], degrade xenobiotics and carbohydrates [54], function as aryl alcohol dehydrogenases to facilitate the degradation of β-aryl ethers in lignin [55], and are induced by exposure to phenolics and aromatic compounds in bacteria and yeasts [56].…”

Section: Resultsmentioning

confidence: 99%

Midgut transcriptome profiling of Anoplophora glabripennis, a lignocellulose degrading cerambycid beetle

et al. 2013

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BackgroundWood-feeding insects often work in collaboration with microbial symbionts to degrade lignin biopolymers and release glucose and other fermentable sugars from recalcitrant plant cell wall carbohydrates, including cellulose and hemicellulose. Here, we present the midgut transcriptome of larval Anoplophora glabripennis, a wood-boring beetle with documented lignin-, cellulose-, and hemicellulose- degrading capabilities, which provides valuable insights into how this insect overcomes challenges associated with feeding in woody tissue.ResultsTranscripts from putative protein coding regions of over 9,000 insect-derived genes were identified in the A. glabripennis midgut transcriptome using a combination of 454 shotgun and Illumina paired-end reads. The most highly-expressed genes predicted to encode digestive-related enzymes were trypsins, carboxylesterases, β-glucosidases, and cytochrome P450s. Furthermore, 180 unigenes predicted to encode glycoside hydrolases (GHs) were identified and included several GH 5, 45, and 48 cellulases, GH 1 xylanases, and GH 1 β-glucosidases. In addition, transcripts predicted to encode enzymes involved in detoxification were detected, including a substantial number of unigenes classified as cytochrome P450s (CYP6B) and carboxylesterases, which are hypothesized to play pivotal roles in detoxifying host tree defensive chemicals and could make important contributions to A. glabripennis’ expansive host range. While a large diversity of insect-derived transcripts predicted to encode digestive and detoxification enzymes were detected, few transcripts predicted to encode enzymes required for lignin degradation or synthesis of essential nutrients were identified, suggesting that collaboration with microbial enzymes may be required for survival in woody tissue.ConclusionsA. glabripennis produces a number of enzymes with putative roles in cell wall digestion, detoxification, and nutrient extraction, which likely contribute to its ability to thrive in a broad range of host trees. This system is quite different from the previously characterized termite fermentation system and provides new opportunities to discover enzymes that could be exploited for cellulosic ethanol biofuel production or the development of novel methods to control wood-boring pests.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-14-850) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Midgut transcriptome profiling of Anoplophora glabripennis, a lignocellulose degrading cerambycid beetle

et al. 2013

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“…In the termite gut, carbohydrate-active enzymes (CAZymes), such as cellulases and hemicellulases, are secreted (i.e., both symbiotic and endogenous enzymes). Additionally, a set of pro-oxidant, antioxidant, and detoxification enzymes (PADs) is also present [5–7]. Among the PADs found in termites, superoxide dismutase (SOD), catalases (CATs), glutathione S-transferase (GST), and aldo–keto reductases (AKRs) have been studied in detail because the transcription of mRNAs encoding these enzymes is upregulated in response to lignocellulose degradation [8].…”

Section: Introductionmentioning

confidence: 99%

The Coptotermes gestroi aldo–keto reductase: a multipurpose enzyme for biorefinery applications

Tramontina

Cairo

Liberato

et al. 2017

Biotechnol Biofuels

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BackgroundIn nature, termites can be considered as a model biological system for biofuel research based on their remarkable efficiency for lignocellulosic biomass conversion. Redox enzymes are of interest in second-generation ethanol production because they promote synergic enzymatic activity with classical hydrolases for lignocellulose saccharification and inactivate fermentation inhibitory compounds produced after lignocellulose pretreatment steps.ResultsIn the present study, the biochemical and structural characteristics of the Coptotermes gestroi aldo–keto reductase (CgAKR-1) were comprehensively investigated. CgAKR-1 displayed major structural differences compared with others AKRs, including the differences in the amino acid composition of the substrate-binding site, providing basis for classification as a founding member of a new AKR subfamily (family AKR1 I). Immunolocalization assays with anti-CgAKR-1 antibodies resulted in strong fluorescence in the salivary gland, proventriculus, and foregut. CgAKR-1 supplementation caused a 32% reduction in phenolic aldehydes, such as furfural, which act as fermentation inhibitors of hemicellulosic hydrolysates, and improved ethanol fermentation by the xylose-fermenting yeast Scheffersomyces stipitis by 45%. We observed synergistic enzymatic interactions between CgAKR-1 and commercial cellulosic cocktail for sugarcane bagasse saccharification, with a maximum synergism degree of 2.17 for sugar release. Our data indicated that additive enzymatic activity could be mediated by reactive oxygen species because CgAKR-1 could produce hydrogen peroxide.ConclusionIn summary, we identified the founding member of an AKRI subfamily with a potential role in the termite digestome. CgAKR-1 was found to be a multipurpose enzyme with potential biotechnological applications. The present work provided a basis for the development and application of integrative and multipurpose enzymes in the bioethanol production chain.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0688-6) contains supplementary material, which is available to authorized users.

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“…With the revolution of "omics" technologies, it is interesting to apply advanced studies on termites such as metagenomics, transcriptomics or proteomics [7][8][9]. These technologies offer the possibility to improve the screening for new enzymes and to study the system as a whole.…”

Section: Introductionmentioning

confidence: 99%

GC×GC-TOFMS for the Analysis of Metabolites Produced by Termites (Reticulitermes flavipes) Bred on Different Carbon Sources

et al. 2016

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Abstract:More and more studies are dedicated to termites and their symbionts, to better understand how they efficiently produce energy from lignocellulose. In that context, a powerful analytical method was developed to perform the detection, separation and identification of compounds in the 1 µL fluid volume of the gut of the termite Reticulitermes flavipes. Comprehensive two-dimensional gas chromatography (GCˆGC) coupled to time-of-flight mass spectrometry (TOFMS) was tested with three different column combinations: (1) low-polar/mid-polar; (2) polar/low-polar and (3) mid-polar/low-polar. The column set (3) offered the best separation and was chosen for further analysis and comparison study. Metabolites were detected in the samples, including amino acids, sugars, amines and organic acids. Samples collected from termites fed for 30 days on Avicel cellulose or xylan powder diets were analyzed and compared with the wood diet. Principal component analysis (PCA) of metabolite profiles demonstrated a separation of different clusters corresponding to the three different diets, with a similar trend for diets containing cellulose. The Analysis of variance (ANOVA) (one way-ANOVA and Tukey's test) was used to compare compound levels between these three different diets. Significant differences were observed, including higher levels of aromatic derivatives in the wood diet and higher levels of sugar alcohols in the xylan diet. A higher accumulation of uric acid was observed with the artificial diets (cellulose and xylan), likely to be related to the nitrogen deficiency. The present study highlighted the capability of adaptation of the termite system to non-optimal carbon sources and the subsequent modification of the metabolite profile. These results demonstrate the potential interest to investigate metabolite profiling with state-of-the-art separation science tools, in order to extract information that could be integrated with other omics data to provide more insight into the termite-symbiont digestion system.

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Lignin-associated metagene expression in a lignocellulose-digesting termite

Cited by 69 publications

References 41 publications

Midgut transcriptome profiling of Anoplophora glabripennis, a lignocellulose degrading cerambycid beetle

Midgut transcriptome profiling of Anoplophora glabripennis, a lignocellulose degrading cerambycid beetle

The Coptotermes gestroi aldo–keto reductase: a multipurpose enzyme for biorefinery applications

GC×GC-TOFMS for the Analysis of Metabolites Produced by Termites (Reticulitermes flavipes) Bred on Different Carbon Sources

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