Functional genomics of stress responses in fish

Our understanding of the mechanisms underlying stress responses in fish remains fragmentary. However, new insights into these mechanisms, and their biological significance, have been provided by investigation at the transcriptional level. Microarray technology has allowed the unbiased analysis of the transcriptome, providing a potentially system-wide overview of stress responses. In this review, we present recently published transcriptomic studies on stress responses in fish exposed to a range of environmental, xenobiotic, social, and aquacultural stressors. Overall, these studies highlight the complexity of transcript patterns, have identified new genes whose expression is significantly modified after exposure to stressors, and have revealed both common and tissue-specific expression signatures. Some shortcomings can be identified including lack of information on the longer-term compensatory or adaptive phases of the stress response, limitations on gene annotation, and the use of pooled mRNA preparations which masks variation between individuals. Nonetheless, although the functional genomic analysis of stress responses in fish is still in its infancy, rapid growth in the number of studies and continued advances in technology and database content will inevitably lead to a fuller understanding of the processes involved and to the identification of novel stress indicators with diagnostic or predictive value.