Meeting Abstract

26.3  Monday, Jan. 4  Transcriptomic responses to heat-stress reveal the molecular basis for the success of invasive mussels LOCKWOOD, Brent L.*; SANDERS, Jon G.; SOMERO, George N.; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University blockwoo@stanford.edu

Invasive species are increasingly important factors in marine ecosystems worldwide. Although many studies have examined the ecological effects of invasives, little is known about physiological mechanisms that might contribute to invasive success, for example, by allowing an invasive species to out-compete and replace a similar, native species. The mussel Mytilus galloprovincialis, a native of the Mediterranean Sea, is a successful invader on the central and southern coasts of California, where it has largely displaced the native congener, Mytilus trossulus. Previously, it has been shown that thermal responses of several physiological traits may underlie the capacity of M. galloprovincialis to out-compete M. trossulus in warm habitats. To elucidate possible differences in stress-induced gene expression between these congeners, we developed an oligonucleotide microarray and used it to study gene expression patterns under conditions of acute thermal stress. The two species exhibited key differences in their transcriptomes during heat-ramp exposures, particularly among genes encoding proteins involved in cellular damage and damage repair. M. trossulus showed higher induction of genes involved in apoptotic (cell death) and proteolytic pathways. Conversely, M. galloprovincialis showed higher induction of genes involved in protein folding, energy metabolism, anti-oxidant activity, and cell cycle control. These different responses to acute heat stress may help to explain—and predict—the invasive success of M. galloprovincialis in a warming world.