Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus

J Invertebr Pathol. 2014 Jan:115:62-7. doi: 10.1016/j.jip.2013.10.003. Epub 2013 Oct 19.

Abstract

The interaction of Mtx toxins from Lysinibacillus sphaericus (formerly Bacillus sphaericus) with Bacillus thuringiensis subsp. israelensis Cry toxins and the influence of such interactions on Cry-resistance were evaluated in susceptible and Cry-resistant Culex quinquefasciatus larvae. Mtx-1 and Mtx-2 were observed to be active against both susceptible and resistant mosquitoes; however varying levels of cross-resistance toward Mtx toxins were observed in the resistant mosquitoes. A 1:1 mixture of either Mtx-1 or Mtx-2 with different Cry toxins generally showed moderate synergism, but some combinations were highly toxic to resistant larvae and suppressed resistance. Toxin synergy has been demonstrated to be a powerful tool for enhancing activity and managing Cry-resistance in mosquitoes, thus Mtx toxins may be useful as components of engineered bacterial larvicides.

Keywords: Cry toxins; Mtx toxins; Resistance; Resistance Management; Synergy.

Publication types

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

MeSH terms

  • Animals
  • Bacillus / chemistry*
  • Bacterial Proteins / toxicity*
  • Culex / microbiology*
  • Endotoxins / toxicity
  • Hemolysin Proteins / toxicity
  • Insecticide Resistance / physiology*
  • Pest Control, Biological / methods*

Substances

  • Bacterial Proteins
  • Endotoxins
  • Hemolysin Proteins