Coevolutionary interactions on two time scales: Bacillus thuringiensis vs Insects

  • Date: Apr 29, 2015
  • Time: 02:00 PM - 03:30 PM (Local Time Germany)
  • Speaker: David G. Heckel
  • Max-Planck-Institute for Chemical Ecology, Jena, Germany
  • Location: Central Building
  • Room: Seminar Room
  • Host: Ralph Bock
Abstract: Certain strains of the gram-positive soil-dwelling bacterium Bacillus thuringiensis (Bt) produce pore-forming toxins that kill insect larvae and nematodes that ingest them, by attacking targets in the midgut. A signature of this long-term coevolutionary interaction between prokaryotes and eukaryotes can be seen in bacterial strategies to diversify and combine different toxins, and in insect strategies to evade or degrade them. Bt toxins are now widely used in spray formulations and in transgenic crops to control insect pests of human agriculture and human health, presenting the opportunity to examine this coevolutionary interaction on a much shorter timescale. In fact, similar to the situation with chemical insecticides, evolution of Bt resistance by the target pests increasingly threatens their sustainable use in agriculture. We describe case studies of recently-evolved Bt resistance in insects to show how microevolutionary steps, some including humans as agents, can inform our understanding of the macroevolutionary patterns resulting from the toxin arms race.
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