Investigating The Grey Field Slug

Abstract

High-throughput sequencing was used to analyse cDNA generated from tissues of the grey field slug, Deroceras reticulatum, a significant invertebrate pest of agricultural and horticultural crops. Almost no sequence data is available for this organism. In this project, we performed de novo transcriptome sequencing to produce sequence dataset for the Deroceras reticulatum.
A total of 132,597 and 161,419 sequencing reads between 50-600bp from the digestive gland and neural tissue were obtained through Roche 454 pyrosequencing. These reads were assembled into contiguous sequences and annotated using sequence homology search tools. Multiple sequence assemblies and annotation data was amalgamated into a biological database using BioSQL. Analysis of the dataset with predictions of probable protein function were made based on annotation data. InterPro (IPR) terms generated with InterProScan software were mapped to read counts and used to identify more frequently sequenced gene families.
Digestive hydrolases were major transcripts in the digestive gland, with cysteine proteinases and cellulases being the most abundant functional classes. A Cathepsin L homologue is likely to be responsible for the proteinase activity of the digestive gland which was previously detected by biochemical analysis. Cathepsin L and several other predicted proteins were used to design RNAi experiments to assess potential for crop pest defence strategy. Further work on protein expression of a native tumour necrosis factor (TNF) ligand homologue was also conducted as an exemplar study.