title: Differential Expression of Genes that Control Respiration Contribute to Thermal Adaptation in Redband Trout (Oncorhynchus mykiss gairdneri).
abstract: Organisms can adapt to local environmental conditions as a plastic response or become adapted through natural selection on genetic variation. The ability to adapt to increased water temperatures will be of paramount importance for many fish species as the climate continues to warm and water resources become limited. Because increased water temperatures will reduce the dissolved oxygen available for fish, we hypothesized that adaptation to low oxygen environments would involve improved respiration through oxidative phosphorylation (OXPHOS). To test this hypothesis, we subjected individuals from two ecologically divergent populations of inland (redband) rainbow trout (Oncorhynchus mykiss gairdneri) with historically different temperature regimes (desert and montane) and their F1 progeny to diel cycles of temperature stress and then examined gene expression data for 80 nuclear- and mitochondrial-encoded OXPHOS subunits that participate in respiration. Of the 80 transcripts, 7 showed ≥ 2-fold difference in expression levels in gill tissue from desert fish under heat stress whereas the montane fish had none and the F1 only had one differentially expressed gene. A structural analysis of the proteins encoded by those genes suggests that the response could coordinate the formation of supercomplexes and oligomers. Supercomplexes may increase the efficiency of respiration because complexes I, III, and IV are brought into close proximity and oligomerization of complex V alters the macrostructure of mitochondria to improve respiration. Significant differences in gene expression patterns in response to heat stress in a common environment indicate that the response was not due to plasticity but had a genetic basis.
authors.affiliation: School of Biological Sciences, Washington State University michael.garvin@wsu.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Garvin
authors.affiliation: School of Biological Sciences, Washington State University.
authors.forename: Gary H
authors.initials: GH
authors.lastname: Thorgaard
authors.affiliation: Columbia River Inter-Tribal Fish Commission, Hagerman, Idaho.
authors.forename: Shawn R
authors.initials: SR
authors.lastname: Narum
mesh_terms: D000064:Acclimatization / Q000235:genetics*; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019069:Cell Respiration; D045222:Electron Transport Chain Complex Proteins / Q000235:genetics* / Q000378:metabolism; D042967:Electron Transport Complex I / Q000235:genetics / Q000378:metabolism; D014450:Electron Transport Complex III / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D054629:Genome, Mitochondrial; D006358:Hot Temperature; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000378:metabolism; D010085:Oxidative Phosphorylation; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism
chemical_list: D045222:Electron Transport Chain Complex Proteins; D029941:Fish Proteins; D020033:Protein Isoforms; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III
keywords: complex I; environmental genomic interaction; hypoxia; mitochondria; positive selection; respiration