Transcriptome analysis of the Japanese pine sawyer beetle, Monochamus alternatus (Coleoptera: Cerambycidae) by high-throughput Illumina sequencing

Abstract

The Japanese pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is a serious pest management concern in pine stands. Although there are currently 1012 expressed tag sequences (ESTs) for M. alternatus deposited in public databases, this number is not sufficient for understanding the molecular biology of this insect. Next-generation sequencing technologies are essential for determining the enormous transcript sequences that are necessary for gene discovery. In the present study, the M. alternatus transcriptome was sequenced using Illumina paired-end sequencing technology. De novo assembling was conducted to generate a collection of 48,787 unigenes (average length 721bp) that represent the first transcriptome of this species. The majority of the unigenes (78.1%) had top matches (first hit) with sequences from Tribolium castaneum (Herbst). Approximately 57.12% and 42.35% of the unigenes had significant similarities with proteins in the National Center for Biotechnology Information (NCBI) non-redundant protein database (Nr) and Swiss-Prot database, respectively. A total of 9005 (18.46%) unigenes were assigned to Clusters of Orthologous Groups (COG), and 13,484 (27.64%) unigenes were assigned to Gene Ontology (GO) categories. A total of 18,915 unigenes had significant matches in the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG) and were assigned to 258 pathways. The unigenes encoding specific genes related to insecticide detoxification and insecticide target enzymes. These results are an invaluable resource for future studies on M. alternatus, especially for studies focused on novel gene discovery and comparative genomics.