Patterns of Gene Expression in Daphnia Experiencing Calcium and Dietary Phosphorus Stress

Session: Poster session

William Kim, Trent University, [email protected]
Aaron Shafer, Trent University, [email protected]
Clay Prater, Trent University, [email protected]
Nicole Wagner, Cornell University, [email protected]
Robert Huber, Trent University, [email protected]
Paul Frost, Trent University, [email protected]

Abstract

Nutritional stress strongly influences animal growth and development. Reduced calcium (Ca) and dietary phosphorus (P) supplies in lakes are known to be tied to ecophysiological responses and taxonomic shifts in freshwater communities. Although the ecophysiological responses of the model freshwater zooplankton, Daphnia pulex, have been well studied, the molecular underpinnings behind these changes are not well-understood. In this study, Ca- and P-limitation effects on gene expression in Daphnia were tested using a factorial nutrient-limitation experiment consisting of high and low Ca and dietary P supply grown over 6 days. We measured changes in growth rate and elemental composition to ensure our nutrient limiting treatment was effective. Total RNA was then extracted from pooled daphniids (~25) grown under all treatment combinations (n = 6) and RNA-seq was performed to examine the differential gene expression patterns. Each nutritional stressor caused unique sets of genes to be differentially expressed, indicating that different biochemical mechanisms were employed by Daphnia in response to each type of stress. Our work provides insight into the molecular responses of Daphnia to different nutritional stressor, and provides the necessary information required to develop bio-indicators that can be used to determine the in situ nutritional state of animals from lakes.

1. Keyword
nutrients

2. Keyword
environmental effects

3. Keyword
genetics

4. Additional Keyword
Zooplankton

5. Additional Keyword
Phosphorus

6. Additional Keyword
Calcium