Transcriptome and metabolite responses to predation in a South Pacific soft coral

Sinularia polydactyla, a dioecious, abundant soft coral in the South Pacific, exhibits biochemical phenotypic plasticity in secondary metabolite production in relation to predation intensity. However, it is unclear to what extent changes in secondary metabolites, such as 11 beta-acetoxypukalide, may result from specific, induced pathway activities at the level of gene expression. To investigate both chemical changes and differences in mRNA diversity in response to predation stress, artificial predation experiments were conducted in situ on colonies of S. polydactyla. Multivariate statistical analyses of coral biochemical metabolites and our kinetic transcriptome profiling technique indicate that that the induction of 11 beta-acetoxypukalide by predation stress likely results from the upregulation of either one dominant transcript or a very small set of transcripts, indicative of a targeted upregulation rather than a generalized, genetic stress response. Overall, this work establishes a routine method for integrating high-throughput transcriptome and metabolome data sets to allow for the identification of metabolites whose intracellular concentrations can be readily linked to gene expression events in response to specific treatments in non-model organisms.