Expression of genes involved in energy mobilization and osmoprotectant synthesis during thermal and dehydration stress in the Antarctic midge, Belgica antarctica

Nicholas M. Teets, Yuta Kawarasaki, Richard E. Lee, David L. Denlinger

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

The Antarctic midge, Belgica antarctica, experiences sub-zero temperatures and desiccating conditions for much of the year, and in response to these environmental insults, larvae undergo rapid shifts in metabolism, mobilizing carbohydrate energy reserves to promote synthesis of low-molecular-mass osmoprotectants. In this study, we measured the expression of 11 metabolic genes in response to thermal and dehydration stress. During both heat and cold stress, we observed upregulation of phosphoenolpyruvate carboxykinase (pepck) and glycogen phosphorylase (gp) to support rapid glucose mobilization. In contrast, there was a general downregulation of pathways related to polyol, trehalose, and proline synthesis during both high- and low-temperature stress. Pepck was likewise upregulated in response to different types of dehydration stress; however, for many of the other genes, expression patterns depended on the nature of dehydration stress. Following fast dehydration, expression patterns were similar to those observed during thermal stress, i. e., upregulation of gp accompanied by downregulation of trehalose and proline synthetic genes. In contrast, gradual, prolonged dehydration (both at a constant temperature and in conjunction with chilling) promoted marked upregulation of genes responsible for trehalose and proline synthesis. On the whole, our data agree with known metabolic adaptations to stress in B. antarctica, although a few discrepancies between gene expression patterns and downstream metabolite contents point to fluxes that are not controlled at the level of transcription.

Original languageEnglish
Pages (from-to)189-201
Number of pages13
JournalJournal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
Volume183
Issue number2
DOIs
StatePublished - Feb 2013

Bibliographical note

Funding Information:
Acknowledgments We thank the staff at Palmer Station for their excellent support during our field season. We acknowledge Justin Peyton for his assistance with the Belgica genome data and for providing the Matlab script for qPCR analysis. We also thank Dr. Tom Teets for help preparing Fig. 1 and Kevin Stevenson for technical assistance with qPCR standard curves. This work was supported in part by NSF OPP-ANT-0837613 and ANT-0837559.

Keywords

  • Antarctic midge
  • Dehydration stress
  • Freeze tolerance
  • Gluconeogenesis
  • Trehalose

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Endocrinology
  • Animal Science and Zoology
  • Biochemistry
  • Physiology

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