Meeting Abstract

139.4  Monday, Jan. 7  Using RNA-Seq and gene-specific methods to examine salinity-induced gene expression changes in an anchialine shrimp HAVIRD, J. C.*; HENRY, R. P.; SANTOS, S. R.; Auburn University; Auburn University; Auburn University jhavird@auburn.edu

Understanding how organisms respond to environmental variation is critical in order to comprehend how they function in their niches. Taxa from the coastal anchialine ecosystem represent good candidates for studying responses to environmental variation since their habitats undergo wide oscillations in physical and chemical properties, like temperature and salinity. Currently, little is known on how anchialine organisms cope with the environmental variation experienced in these habitats. To address this, we investigated how the Hawaiian anchialine shrimp Halocaridina rubra responds to changing salinity via analyses of gene expression. Illumina technology was first used to sequence transciptomes from two H. rubra genetic lineages (from East Hawaii and Windward Oahu) previously identified based on divergence in their mitochondrial COI. Six known crustacean osmoregulatory genes were identified from this transcriptomic data and targeted for expression analyses using qPCR. The expression levels of these genes remained relatively constant, or decreased, when shrimp were transferred from iso-osmotic conditions (32‰) to either hyper-regulatory (15‰ and 2‰) or hypo-regulatory (45‰) conditions. This is in contrast to previously studied crustaceans, which tend to upregulate these genes during salinity transfer. These and previous results suggest that alternative or novel osmoregulatory genes, pathways, or mechanisms may be utilized by H. rubra to cope with the rapidly changing salinities experienced in anchialine habitats. Ongoing experiments utilizing RNA-Seq will investigate salinity-induced gene expression changes across the entire H. rubra transcriptome and shed light on this possibility.