Transcriptomic Analysis of Eucryptorrhynchus chinensis (Coleoptera: Curculionidae) Using 454 Pyrosequencing Technology

Abstract

Eucryptorrhynchus chinensis Olivier (Coleoptera: Curculionidae) is one of the most important pests of Ailanthus altissima; however, so far, no studies on the genome or transcriptome of E. chinensis have been reported. Using the Roche 454 FLX Titanium platform, an RNA pool obtained from E. chinensis eggs, larva, pupae, and adults was sequenced and assembled de novo to achieve maximum diversity of sampled transcripts. We obtained 1,441,137 (∼518 Mb) raw reads with an average length of 360 bp. After trimming, 89% qualified reads were produced and assembled into 35,509 isotigs with an average length of 440 bp, N50 of 1,048 bp, and 111,643 singletons. We generated 87,894 unigenes following a cluster analysis of the isotigs and singletons, and then functionally annotated the unigenes with gene descriptions. We obtained 23,363 GO assignments, and 12,724 unigenes were assigned to KOG. Based on these annotations, 294 biochemical pathways involved in growth, reproduction, and stress or immune responses were predicted. A total of 659,026 single nucleotide variants and 6,112 simple sequence repeats were detected. Our data provide comprehensive information on the sequence and possible functions of E. chinensis transcripts.