Retracing the evolutionary path that led to flea-borne transmission of Yersinia pestis

Cell Host Microbe. 2014 May 14;15(5):578-86. doi: 10.1016/j.chom.2014.04.003.

Abstract

Yersinia pestis is an arthropod-borne bacterial pathogen that evolved recently from Yersinia pseudotuberculosis, an enteric pathogen transmitted via the fecal-oral route. This radical ecological transition can be attributed to a few discrete genetic changes from a still-extant recent ancestor, thus providing a tractable case study in pathogen evolution and emergence. Here, we determined the genetic and mechanistic basis of the evolutionary adaptation of Y. pestis to flea-borne transmission. Remarkably, only four minor changes in the bacterial progenitor, representing one gene gain and three gene losses, enabled transmission by flea vectors. All three loss-of-function mutations enhanced cyclic-di-GMP-mediated bacterial biofilm formation in the flea foregut, which greatly increased transmissibility. Our results suggest a step-wise evolutionary model in which Y. pestis emerged as a flea-borne clone, with each genetic change incrementally reinforcing the transmission cycle. The model conforms well to the ecological theory of adaptive radiation.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Biofilms
  • Biological Evolution*
  • Female
  • Humans
  • Insect Vectors / microbiology*
  • Male
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Phylogeny
  • Siphonaptera / microbiology*
  • Yersinia Infections / microbiology
  • Yersinia Infections / transmission*
  • Yersinia pestis / classification
  • Yersinia pestis / genetics*
  • Yersinia pestis / physiology
  • Yersinia pseudotuberculosis / classification
  • Yersinia pseudotuberculosis / genetics
  • Yersinia pseudotuberculosis / physiology

Substances

  • Bacterial Proteins