Pyrosequencing-based transcriptomic resources in the pond snail Lymnaea stagnalis, with a focus on genes involved in molecular response to diquat-induced stress

Abstract

Due to their ability to explore whole genome response to drugs and stressors, omics-based approaches are widely used in toxicology and ecotoxicology, and identified as powerful tools for future ecological risk assessment and environmental monitoring programs. Understanding the long-term effects of contaminants may indeed benefit from the coupling of genomics and eco-evolutionary hypotheses. Next-generation sequencing provides a new way to investigate pollutants impact, by targeting early responses, screening chemicals, and directly quantifying gene expression, even in organisms without reference genome. Lymnaea stagnalis is a freshwater mollusk in which access to genomic resources is critical for many scientific issues, especially in ecotoxicology. We used 454-pyrosequencing to obtain new transcriptomic resources in L. stagnalis and to preliminarily explore gene expression response to a redox-cycling pesticide, diquat. We obtained 151,967 and 128,945 high-quality reads from control and diquat-exposed individuals, respectively. Sequence assembly provided 141,999 contigs, of which 124,387 were singletons. BlastX search revealed significant match for 34.6 % of the contigs (21.2 % protein hits). KEGG annotation showed a predominance of hits with genes involved in energy metabolism and circulatory system, and revealed more than 400 putative genes involved in oxidative stress, cellular/molecular stress and signaling pathways, apoptosis, and metabolism of xenobiotics. Results also suggest that diquat may have a great diversity of molecular effects. Moreover, new genetic markers (putative SNPs) were discovered. We also created a Ensembl-like web-tool for data-mining ( http://genotoul-contigbrowser.toulouse.inra.fr:9095/Lymnaea_stagnalis/index.html ). This resource is expected to be relevant for any genomic approach aimed at understanding the molecular basis of physiological and evolutionary responses to environmental stress in L. stagnalis.

Identification of genes related to learning and memory in the brain transcriptome of the mollusc,Hermissenda crassicornis

“…A limited number of molecular-level studies have been performed on Hermissenda in these areas (Nelson and Alkon 1988;Crow et al 1997). Broader-scale genetic experiments, such as identification of genes or specific genetic isoforms that produce proteins involved in Hermissenda associative learning, have been impossible without more extensive genetic information specifically from Hermissenda.Transcriptomes have been sequenced in a small number of other gastropod species, including neuronal transcriptomes from Aplysia californica (Moroz et al 2006;Fiedler et al 2010;Heyland et al 2011), A. kurodai (Lee et al 2008Choi et al 2010), Lymnaea stagnalis (Bouetard et al 2012;Sadamoto et al 2012), and Tritonia diomedea (Senatore et al 2015), which have been used in studies of learning and other aspects of neuroscience. The field of molluscan neurogenomics is growing thanks in large part to recent advances in sequencing technologies, which allow larger amounts of transcriptomic information to be sequenced at lower costs compared with technologies available a few years ago.…”

“…Transcriptomes have been sequenced in a small number of other gastropod species, including neuronal transcriptomes from Aplysia californica (Moroz et al 2006;Fiedler et al 2010;Heyland et al 2011), A. kurodai (Lee et al 2008;Choi et al 2010), Lymnaea stagnalis (Bouetard et al 2012;Sadamoto et al 2012), and Tritonia diomedea (Senatore et al 2015), which have been used in studies of learning and other aspects of neuroscience. The field of molluscan neurogenomics is growing thanks in large part to recent advances in sequencing technologies, which allow larger amounts of transcriptomic information to be sequenced at lower costs compared with technologies available a few years ago.…”

Cross-platform metabolic profiling: application to the aquatic model organism Lymnaea stagnalis

“…As a result of the growing interest in this aquatic species in many research fields, transcriptomic studies have been carried out to increase L. stagnalis annotated genes. The transcriptomic expression of different organs has been explored and the genomic response to a pesticide exposure has been investigated [14]. The neuronal transcriptome sequencing has been interest of several recent studies on L. stagnalis CNS [15,16].…”

Proteomic Analysis of the Reproductive Organs of the Hermaphroditic Gastropod Lymnaea stagnalis Exposed to Different Endocrine Disrupting Chemicals

“…Even though our knowledge of mollusc endocrinology is rather limited, the neurohormonal control of reproduction is reasonably well understood in L. stagnalis [15-17]. Moreover, genomic resources have recently been improved by pyrosequencing of cDNAs from L. stagnalis , expanding the databases for protein identification in genomic and proteomic approaches for this species [18]. Finally, this species has been proposed as a candidate species for the development of guidelines for the testing and the assessment of endocrine disruptors in molluscs [19].…”