De novo assembly of the transcriptome of an invasive snail and its multiple ecological applications.

Studying how invasive species respond to environmental stress at the molecular level can help us assess their impact and predict their range expansion. Development of markers of genetic polymorphism can help us reconstruct their invasive route. However, to conduct such studies requires the presence of substantial amount of genomic resources. This study aimed to generate and characterize genomic resources using high throughput transcriptome sequencing for Pomacea canaliculata, a nonmodel gastropod indigenous to Argentina that has invaded Asia, Hawaii and southern United States. De novo assembly of the transcriptome resulted in 128,436 unigenes with an average length of 419 bp (range: 150-8556 bp). Many of the unigenes (2439) contained transposable elements, showing the existence of a source of genetic variability in response to stressful conditions. A total of 3196 microsatellites were detected in the transcriptome; among 20 of the randomly tested microsatellites, 10 were validated to exhibit polymorphism. A total of 15,412 single-nucleotide polymorphisms (SNPs) were detected in the ORFs. LC-MS/MS analysis of the proteome of juveniles revealed 878 proteins, of which many are stress related. This study has demonstrated the great potential of high throughput DNA sequencing for rapid development of genomic resources for a nonmodel organism. Such resources can facilitate various molecular ecological studies, such as stress physiology and range expansion.