Nosema Tolerant Honeybees (Apis mellifera) Escape Parasitic Manipulation of Apoptosis

PLoS One. 2015 Oct 7;10(10):e0140174. doi: 10.1371/journal.pone.0140174. eCollection 2015.

Abstract

Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular organisms. Although numerous intracellular pathogens are known to interfere with the host's apoptotic machinery to overcome this defence, its importance for host-parasite coevolution has been neglected. We conducted three inoculation experiments to investigate in the apoptotic respond during infection with the intracellular gut pathogen Nosema ceranae, which is considered as potential global threat to the honeybee (Apis mellifera) and other bee pollinators, in sensitive and tolerant honeybees. To explore apoptotic processes in the gut epithelium, we visualised apoptotic cells using TUNEL assays and measured the relative expression levels of subset of candidate genes involved in the apoptotic machinery using qPCR. Our results suggest that N. ceranae reduces apoptosis in sensitive honeybees by enhancing inhibitor of apoptosis protein-(iap)-2 gene transcription. Interestingly, this seems not be the case in Nosema tolerant honeybees. We propose that these tolerant honeybees are able to escape the manipulation of apoptosis by N. ceranae, which may have evolved a mechanism to regulate an anti-apoptotic gene as key adaptation for improved host invasion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Bees / cytology*
  • Bees / genetics
  • Bees / parasitology*
  • Bees / physiology
  • Gene Expression Regulation
  • Host-Parasite Interactions*
  • Inhibitor of Apoptosis Proteins / genetics
  • Insect Proteins / genetics
  • Microsporidiosis / genetics
  • Microsporidiosis / veterinary*
  • Nosema / physiology*

Substances

  • Inhibitor of Apoptosis Proteins
  • Insect Proteins

Grants and funding

This study was funded by the Deutsche Forschungsgemeinschaft through the priority programme "Host-Parasite Coevolution – Rapid Reciprocal Adaptation and its Genetic Basis" (SPP 1399, Grant number MO373/26-2) to RFAM and a scholarship from The Foundation for the Preservation of Honey Bees, Inc. to CK.