Identification and expression of proteolysis-response genes for Macrophthalmus japonicus exposure to irgarol toxicity

¹ Faculty of Marine Technology, Chonnam National University, Yeosu 550-749, Korea
² Department of Aqualife Medicine, Chonnam National University, Yeosu 550-749, Korea

^* Corresponding author: iskwak@chonnam.ac.kr, inkwak@hotmail.com

Received: 12 January 2015
Accepted: 29 June 2015

Abstract

Macrophthalmus japonicus is one of the most abundant macrobenthic animals in estuarine zone, which are transition areas between freshwater and marine environments. The crabs are potential bio-indicators reflecting aquatic sediment toxicity. So far, limited genetic research has focused on this group of animals largely due to the limited genomic information. In this study, we performed de novo transcriptome sequencing to produce the most comprehensive expressed sequence tag resource for M. japonicus, and identified stress response genes in M. japonicus exposed to antifouling biocides irgarol. Using 454 pyrosequencing, a total of 887 690 reads were obtained, which were assembled into 24 217 high-quality expressed sequence tags. These contigs were then clustered into 17 289 isotigs and further grouped into 12 923 isogroups. About 48% of the isogroups showed significant matches to known proteins based on sequence similarity. Moreover, irgarol toxicity induced up-regulation of stress response genes, associated with proteolysis and oxidation–reduction in biological process by Gene ontology analyses. Our data provide the most comprehensive transcriptome resource available for M. japonicus. This resource allowed us to identify genes associated with proteolysis processes, which facilitated the quantitative analysis of differential gene expression respond to irgarol toxicity. These data would provide foundation for future genetic and genomic studies of crustacean species and monitoring to freshwater as well as marine ecosystems.