Meeting Abstract

S6.4  Monday, Jan. 5  Transcriptome profiling in the sea urchin: understanding allelochemical modes of action and marine herbivore cellular defenses WHALEN, Kristen*; HOFMANN, Gretchen; STEINBERG, Peter; Univ. New South Wales / Univ. of California, Santa Barbara; University of California, Santa Barbara; University of New South Wales, Sydney, Australia kwhalen@whoi.edu

As marine ecologists struggle to explain the vast differences in herbivore tolerance to plant allelochemicals, a key piece of the puzzle requires understanding the cellular and molecular responses underlying diet choice. Since herbivore biochemical and molecular adaptations are likely to be complex, genomic-based approaches are poised to accelerate our understanding of the physiological underpinnings controlling an herbivores response to dietary chemical stressors. Specifically, we are investigating the transcriptome-level response to varying algal diets and specific secondary metabolites in Australian sea urchin species. Sea urchins grazers dominate shallow seas worldwide and have had the most impact of any marine herbivore on structuring populations and communities of benthic macroalgae. This interaction has no doubt influenced the evolution of seaweed chemical defenses, and in turn, the coevolution of herbivore detoxification genes. Working with colleagues in the Hofmann lab, we have designed a custom sea urchin oligo microarray containing over 2000 genes involved in xenobiotic biotransformation/efflux, signal transduction, metabolism, oxidative stress and chemoreception. This technology will allow us to determine the cellular targets of algal secondary metabolites and identify those genes involved in xenobiotic resistance essentially creating a transcriptomic fingerprint of an organisms stress response. Discussion will focus on the use of the sea urchin microarray as a tool for understanding the coordinately-controlled xenobiotic defense gene network in marine herbivores using a toxicogenomics framework.