<p class="first" id="P1">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
<i>Callinectes sapidus</i>, 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
<i>C. sapidus</i> 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 (~10–15 M), but with increased biological
replication, be utilized in future DEG analyses of crustaceans.
</p>