Diversification, Evolution and Sub-Functionalization of 70kDa Heat-Shock Proteins in Two Sister Species of Antarctic Krill: Differences in Thermal Habitats, Responses and Implications under Climate Change
| Type | Article | ||||||||
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| Date | 2015-04 | ||||||||
| Language | English | ||||||||
| Author(s) | Cascella Kevin1, 2, Jollivet Didier1, 2, Papot Claire3, Leger Nelly4, 5, Corre Erwan6, 7, Ravaux Juliette4, 5, Clark Melody S.8, Toullec Jean-Yves1, 2 | ||||||||
| Affiliation(s) | 1 : Univ Paris 06, Univ Paris 04, CNRS, Equipe ABICE,Stn Biol Roscoff,UMR 7144, F-29680 Roscoff, France. 2 : CNRS, Stn Biol Roscoff, Adaptat & Div Milieu Marin, UMR 7144, F-29680 Roscoff, France. 3 : Univ Lille 1, CNRS, Ecoimmunol Marine Annelids, UMR8198, F-59655 Villeneuve Dascq, France. 4 : Univ Paris 06, Univ Paris 04, CNRS, Equipe AMEX,UMR 7208, F-75005 Paris, France. 5 : Univ Paris 06, CNRS 7208, BOREA, F-75005 Paris, France. 6 : Univ Paris 06, Univ Paris 04, CNRS,ABiMS,FR 2424, Anal & Bioinformat Marine Sci,Stn Biol Roscoff, F-29680 Roscoff, France. 7 : CNRS, Stn Biol Roscoff, FR 2424, F-29680 Roscoff, France. 8 : British Antarctic Survey, NERC, Cambridge CB3 0ET, England. |
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| Source | Plos One (1932-6203) (Public Library Science), 2015-04 , Vol. 10 , N. 4 , P. e0121642 | ||||||||
| DOI | 10.1371/journal.pone.0121642 | ||||||||
| WOS© Times Cited | 36 | ||||||||
| Abstract | BackgroundA comparative thermal tolerance study was undertaken on two sister species of Euphausiids (Antarctic krills) Euphausia superba and Euphausia crystallorophias. Both are essential components of the Southern Ocean ecosystem, but occupy distinct environmental geographical locations with slightly different temperature regimes. They therefore provide a useful model system for the investigation of adaptations to thermal tolerance. Methodology/Principal FindingInitial CTmax studies showed that E. superba was slightly more thermotolerant than E. crystallorophias. Five Hsp70 mRNAs were characterized from the RNAseq data of both species and subsequent expression kinetics studies revealed notable differences in induction of each of the 5 orthologues between the two species, with E. crystallorophias reacting more rapidly than E. superba. Furthermore, analyses conducted to estimate the evolutionary rates and selection strengths acting on each gene tended to support the hypothesis that diversifying selection has contributed to the diversification of this gene family, and led to the selective relaxation on the inducible C form with its possible loss of function in the two krill species. ConclusionsThe sensitivity of the epipelagic species E. crystallorophias to temperature variations and/or its adaptation to cold is enhanced when compared with its sister species, E. superba. These results indicate that ice krill could be the first of the two species to be impacted by the warming of coastal waters of the Austral ocean in the coming years due to climate change. |
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