Identification, Distribution and Population Dynamics of Francisella-like Endosymbiont in Haemaphysalis doenitzi (Acari: Ixodidae)

Sci Rep. 2016 Oct 12;6:35178. doi: 10.1038/srep35178.


Francisella-like endosymbionts (FLEs) with significant homology to Francisella tularensis (γ-proteobacteria) have been characterized in several tick species, whereas knowledge on their distribution and population dynamics in ticks remains meager. Hence, in the current study, we identified a novel Francisella-like endosymbiont (FLEs-Hd) from the tick Haemaphysalis doenitzi and evaluated the putative functions of this symbiont. Results indicated that FLEs-Hd had 100% infection rate and a perfect vertical transmission in H. doenitzi, and that it is distributed in ovaries, malpighian tubules, salivary glands and midguts of the ticks, suggesting that FLEs-Hd presumably is a crucial symbiont of the host without specific tissue tropism. To further explore the function of the symbiont, the population dynamics of FLEs-Hd at each developmental stage of ticks and in tissues at different reproductive statuses were determined by real-time quantitative polymerase chain reaction (real-time qPCR). Results showed that the high density and regular population dynamics of FLEs-Hd appeared in female ovaries, suggesting that the symbiont may provide necessary nutrients or regulators to ensure normal ovary development of ticks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA, Bacterial / genetics
  • DNA, Ribosomal / genetics
  • Female
  • Francisella / classification*
  • Francisella / genetics
  • Francisella / physiology
  • Genes, Bacterial
  • Ixodidae / growth & development
  • Ixodidae / microbiology*
  • Ixodidae / physiology
  • Male
  • Microscopy, Electron, Transmission
  • Phylogeny
  • Symbiosis


  • DNA, Bacterial
  • DNA, Ribosomal