STILLMAN, Jonathon H*; TERANISHI, Kristen S; Romberg Tiburon Center, San Francsico State University; University of Hawaii at Manoa: Transcriptome changes during thermal acclimation, acclimatization, and stress in porcelain crabs

The thermal phenotype of an organism (i.e., heat tolerance, cold tolerance, eurythermality) is an essential determinant of performance across thermal environments and in response to thermal stress. We are working to understand the mechanistic bases of thermal phenotype by analysis of correlated changes between transcriptome profiles and cardiac thermal performance of thermally acclimated porcelain crabs, Petrolisthes cinctipes. Crabs were acclimated for 28 days to 8�C or 18�C, at which time cardiac upper and lower thermal performance limits significantly differ. On day 29, crabs were swapped between 8�C and 18�C. Transcriptome profiles were generated from crabs sampled during days 27-31 of the experiment using cDNA microarrays of 13,824 cloned ESTs from P. cinctipes. R/maanova was used to identify ESTs that had significantly different expression profiles between pre-swap and 12h intervals post-swap. Following transfer of 8�C-acclimated crabs to 18�C, 4957 ESTs had significant changes in expression. In contrast, 1400 ESTs had significant changes in gene expression following transfer of 18�C acclimated crabs to 8�C. Only 300 ESTs were identified as having significant changes in expression in both groups of crabs, indicating that different sets of genes are involved in achieving warm and cold acclimation states. Functional characterization of genes expressed in both groups of crabs as well as those expressed only during warm or cold acclimation is underway. I will also present an overview of our studies to examine variation in thermal phenotype in an ecological context by examination of acclimatization across natural thermal gradients as well as responses to thermal stresses common in intertidal zone habitats. Supported by NSF IOB 0533920 and DOE JGI CSP2006.