title: H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.
abstract: Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits.
authors.affiliation: Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Tobler
authors.affiliation: Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA.
authors.forename: Chathurika
authors.initials: C
authors.lastname: Henpita
authors.affiliation: Center for Veterinary Health Sciences, Oklahoma State University, 205 McElroy Hall, Stillwater, OK 74078, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Bassett
authors.affiliation: School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164, USA.
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Kelley
authors.affiliation: Department of Zoology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK 74078, USA. Electronic address: jennifer.h.shaw@okstate.edu.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Shaw
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D017753:Ecosystem; D004777:Environment; D005786:Gene Expression Regulation / Q000187:drug effects*; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000633:toxicity*; D011036:Poecilia / Q000235:genetics*
chemical_list: D006862:Hydrogen Sulfide
keywords: Adaptation; Extreme environments; Gene expression; H(2)S homeostasis; Hydrogen sulfide; Plasticity; Poecilia mexicana (Poeciliidae)