Transcriptomic responses of the calanoid copepod Calanus finmarchicus to the saxitoxin producing dinoflagellate Alexandrium fundyense.

Vittoria Roncalli,Petra H Lenz,Matthew C Cieslak

doi:10.1038/srep25708

Abstract

In the Gulf of Maine, the copepod Calanus finmarchicus co-occurs with the neurotoxin-producing dinoflagellate, Alexandrium fundyense. The copepod is resistant to this toxic alga, but little is known about other effects. Gene expression profiles were used to investigate the physiological response of females feeding for two and five days on a control diet or a diet containing either a low or a high dose of A. fundyense. The physiological responses to the two experimental diets were similar, but changed between the time points. At 5-days the response was characterized by down-regulated genes involved in energy metabolism. Detoxification was not a major component of the response. Instead, genes involved in digestion were consistently regulated, suggesting that food assimilation may have been affected. Thus, predicted increases in the frequency of blooms of A. fundyense could affect C. finmarchicus populations by changing the individuals’ energy budget and reducing their ability to build lipid reserves.

Highlights

Which involves changes in the expression of 1,000 or more genes[13,15,16,17]
In the Gulf of Maine and Bay of Fundy, the calanoid C. finmarchicus co-occurs with the saxitoxin-producing dinoflagellate A. fundyense, which during bloom conditions can reach densities of 10–100 cells/mL−1 8,9
More recently it has been shown that A. fundyense decreases the reproductive potential of C. finmarchicus females[12]

Summary

Introduction

Which involves changes in the expression of 1,000 or more genes[13,15,16,17]. Features of the CSR are: 1) up-regulation of stress proteins to counteract damage to cellular macromolecules; 2) redistribution of metabolic resources away from ‘energetically expensive’ functions; 3) the arrest of the cell cycle; and 4) apoptosis (in the case of extreme conditions)[13]. RNA-Seq was used to determine relative gene expression in adult females after 2 and 5 days feeding on either a control or one of two experimental diets. Functional analysis was used to test the hypotheses that the copepod physiological response would be characterized by 1) the up-regulation of detoxification pathways as part of a general cellular stress response (CSR) and 2) the persistence of up-regulation of detoxification pathways over time

Objectives

Methods

Results

Conclusion