title: Salinity-induced changes in gene expression from anterior and posterior gills of Callinectes sapidus (Crustacea: Portunidae) with implications for crustacean ecological genomics.
abstract: Decapods represent one of the most ecologically diverse taxonomic groups within crustaceans, making them ideal to study physiological processes like osmoregulation. However, prior studies have failed to consider the entire transcriptomic response of the gill - the primary organ responsible for ion transport - to changing salinity. Moreover, the molecular genetic differences between non-osmoregulatory and osmoregulatory gill types, as well as the hormonal basis of osmoregulation, remain underexplored. Here, we identified and characterized differentially expressed genes (DEGs) via RNA-Seq in anterior (non-osmoregulatory) and posterior (osmoregulatory) gills during high to low salinity transfer in the blue crab Callinectes sapidus, a well-studied model for crustacean osmoregulation. Overall, we confirmed previous expression patterns for individual ion transport genes and identified novel ones with salinity-mediated expression. Notable, novel DEGs among salinities and gill types for C. sapidus included anterior gills having higher expression of structural genes such as actin and cuticle proteins while posterior gills exhibit elevated expression of ion transport and energy-related genes, with the latter likely linked to ion transport. Potential targets among recovered DEGs for hormonal regulation of ion transport between salinities and gill types included neuropeptide Y and a KCTD16-like protein. Using publically available sequence data, constituents for a "core" gill transcriptome among decapods are presented, comprising genes involved in ion transport and energy conversion and consistent with salinity transfer experiments. Lastly, rarefication analyses lead us to recommend a modest number of sequence reads (~10-15M), but with increased biological replication, be utilized in future DEG analyses of crustaceans.
authors.affiliation: Department of Biological Sciences, Molette Laboratory for Climate Change and Environmental Studies, Auburn University, 101 Rouse Life Sciences Bldg., Auburn, AL 36849, USA; Dept. of Biology, Colorado State University, Room E106 Anatomy/Zoology Building, Fort Collins, CO 80523, USA. Electronic address: Justin.Havird@colostate.edu.
authors.forename: Justin C
authors.initials: JC
authors.lastname: Havird
authors.affiliation: Dept. of Biological Sciences, Auburn University, 101 Rouse Life Sciences Bldg., Auburn, AL 36849, USA; Walter Reed Biosystematics Unit, 4210 Silver Hill Rd, Suitland, MD, 20746, USA.
authors.forename: Reed T
authors.initials: RT
authors.lastname: Mitchell
authors.affiliation: Dept. of Biological Sciences, Auburn University, 101 Rouse Life Sciences Bldg., Auburn, AL 36849, USA.
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Henry
authors.affiliation: Department of Biological Sciences, Molette Laboratory for Climate Change and Environmental Studies, Auburn University, 101 Rouse Life Sciences Bldg., Auburn, AL 36849, USA.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Santos
mesh_terms: D000818:Animals; D003386:Brachyura / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D020869:Gene Expression Profiling; D016678:Genome / Q000235:genetics; D023281:Genomics / Q000379:methods*; D005880:Gills / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods*; D058977:Molecular Sequence Annotation; D010802:Phylogeny; D054712:Salinity; D059467:Transcriptome / Q000187:drug effects / Q000235:genetics*
keywords: Crustacean transcriptomics; Gill physiology; Osmoregulation; RNA-Seq; Read depth