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

Abstract

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.

Genome of the Asian longhorned beetle (Anoplophora glabripennis), a globally significant invasive species, reveals key functional and evolutionary innovations at the beetle–plant interface

“…Successful feeding on woody plants therefore requires specialized metabolic adaptations. The genomes of A. glabripennis and certain other phytophagous beetles are known to contain genes encoding plant cell wall degrading enzymes (PCWDEs) [7–9]. PCWDEs degrade cellulose, hemicellulose, or pectin (the main polysaccharide networks in plant cell walls), liberating sugars, minerals, and other nutrients from woody plant tissues.…”

Endogenous cellulolytic enzyme systems in the longhorn beetle <italic>Mesosa myops</italic> (Insecta: Coleoptera) studied by transcriptomic analysis

“…GH5 cellulases from longhorn beetles form a monophyletic branch in the phylogenetic tree, indicating that the GH5 cellulases share a common ancestor. Several Lamiinae longhorn beetles contain relatively large numbers of GH5 cellulase copies [28,36]. This situation is special and has seldom been reported in insects.…”

“…The expansion of GH5 cellulases in longhorn beetles, including M. myops, is therefore a rather unique phenomenon in insects. Recently, GH5 cellulases have also been identified, using transcriptomic methods, in the Cerambycid species A. glabripennis [28] and Apriona japonica [36]. It is well known that longhorn beetle larvae can ingest wood materials and therefore cellulose is the main carbon source for their metabolism and growth.…”

“…All of the arthropod GH5 cellulases are derived from insects, specifically from longhorn beetles (CZAY and GenBank). The seven GH5 cellulases identified in this study together with the GH5 cellulases obtained from other longhorn beetle species [5,10,28,34] were included in the tree building. The phylogeny relationship (Fig.…”

“…But patent sequences, repeated sequences, and sequences with lengths too short or too long were excluded in the analyses. The related cellulase genes of another longhorn beetle, Anoplophora glabripennis [28], were also included in the subsequent analyses. The data matrixes are provided in Supplementary data.…”