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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC CHARACTERIZATION AND IMPROVEMENT OF SHELLFISH BREEDING STOCKS FOR THE PACIFIC NORTHWEST

Location: Forage Seed and Cereal Research

Title: Transcriptome profiling of selectively bred Pacific oyster Crassostrea gigas families that differ in tolerance of heat shock

Authors
item Lang, R -
item Bayne, Christopher -
item Camara, Mark
item Cunningham, Charles -
item Jenny, Matthew -
item Langdon, Christopher -

Submitted to: Marine Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 13, 2009
Publication Date: February 10, 2009
Citation: Lang, R.P., Bayne, C.J., Camara, M.D., Cunningham, C., Jenny, M.J., Langdon, C.J. 2009. Transcriptome profiling of selectively bred Pacific oyster Crassostrea gigas families that differ in tolerance of heat shock. Marine Biotechnology. 11:650-668.

Interpretive Summary: Sessile inhabitants of marine intertidal environments commonly face heat stress, an important component of summer mortality syndrome in the Pacific oyster Crassostrea gigas. Marker-aided selection programs would be useful for developing oyster strains that resist summer mortality; however, there is currently a need to identify candidate genes associated with stress tolerance and to develop molecular markers associated with those genes. To identify candidate genes for further study, we used cDNA microarrays identify genes whose expression patterns differ between families that are sensitive versus tolerant of heat shock. in their transcriptional responses to stress. We identified 110 differentially expressed genes using microarray analysis and verified differential transcription of 15 of these using real-time quantitative polymerase chain reaction. Expression increased after heat shock for genes encoding heat shock proteins and genes for proteins that synthesize lipids, protect against bacterial infection, and regulate spawning, whereas transcription decreased for genes that produce proteins that mobilize lipids and detoxify reactive oxygen species. Genes encoding heat shock protein 27, collagen, putative peroxinectin, putative S-crystallin, and two genes with no match in Genbank had higher transcript concentrations in low-surviving families than in high-surviving families, whereas concentration of cystatin B mRNA was greater in high-surviving families. These genes should be studied further for use in marker-aided selection programs.

Technical Abstract: Sessile inhabitants of marine intertidal environments commonly face heat stress, an important component of summer mortality syndrome in the Pacific oyster Crassostrea gigas. Marker-aided selection programs would be useful for developing oyster strains that resist summer mortality; however, there is currently a need to identify candidate genes associated with stress tolerance and to develop molecular markers associated with those genes. To identify candidate genes for further study, we used cDNA microarrays to test the hypothesis that oyster families that had high (>65%) or low (<30%) survival of heat shock (43°C, 1 h) differ in their transcriptional responses to stress. We extracted total RNAs from gills of two high- and two low-surviving families before and at 1, 3, 6, and 24 h after oysters experienced a non-lethal heat shock (40°C, 1 h). The mRNAs from each family, sampling time, and biological replicate were hybridized to single microarrays. We used an analysis of variance to detect significant differences in transcript concentrations among sampling times, between low- and high-surviving families, and significant interactions between these factors. The concentrations of 110 ESTs varied significantly among sampling times. We verified differential transcription of 15 ESTs using real-time quantitative PCR. Transcription increased after heat shock for genes encoding heat shock proteins and genes for proteins that synthesize lipids, protect against bacterial infection, and regulate spawning, whereas transcription decreased for genes that produce proteins that mobilize lipids and detoxify reactive oxygen species. RNAs encoding heat shock protein 27, collagen, putative peroxinectin, putative S-crystallin, and two genes with no match in Genbank had higher transcript concentrations in low-surviving families than in high-surviving families, whereas concentration of cystatin B mRNA was greater in high-surviving families. These ESTs should be studied further for use in marker-aided selection programs. Low survival of heat shock could result from a complex interaction of cell damage, opportunistic infection, and metabolic exhaustion.

Last Modified: 8/30/2014
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