title: Transcriptomes reveal the genetic mechanisms underlying ionic regulatory adaptations to salt in the crab-eating frog.
abstract: The crab-eating frog, Fejervarya cancrivora, is the only frog that lives near seas. It tolerates increased environmental concentrations of sodium, chloride and potassium partly by raising ion and urea levels in its blood plasma. The molecular mechanism of the adaptation remains rarely documented. Herein, we analyze transcriptomes of the crab-eating frog and its closely related saline-intolerant species, F. limnocharis, to explore the molecular basis of adaptations to such extreme environmental conditions. Analyses reveal the potential genetic mechanism underlying the adaptation to salinity for the crab-eating frog. Genes in categories associated with ion transport appear to have evolved rapidly in F. cancrivora. Both positively selected and differentially expressed genes exhibit enrichment in the GO category regulation of renal sodium excretion. In this category, the positively selected sites of ANPEP and AVPR2 encode CD13 and V2 receptors, respectively; they fall precisely on conserved domains. More differentially expressed rapidly evolved genes occur in the kidney of F. cancrivora than in F. limnocharis. Four genes involved in the regulation of body fluid levels show signs of positive selection and increased expression. Significant up-regulation occurs in several genes of F. cancrivora associated with renin-angiotensin system and aldosterone-regulated sodium reabsorption pathways, which relate to osmotic regulation.
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.|Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Shao
authors.affiliation: College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wang
authors.affiliation: Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhong
authors.affiliation: College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Hong
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Hong-Man
authors.initials: HM
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.|Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ont., M5S2C6, Canada.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Murphy
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.|Laboratory for Conservation and Utilization of Bio-resources, Yunnan University, Kunming 650091, China.
authors.forename: Ya-Ping
authors.initials: YP
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, and Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Che
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D029845:Amphibian Proteins / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D001001:Anura / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D012965:Sodium Chloride; D059467:Transcriptome / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D029845:Amphibian Proteins; D012965:Sodium Chloride