Bacillus thuringiensis Cry11Ba works synergistically with Cry4Aa but not with Cry11Aa for toxicity against mosquito Culex pipiens (Diptera: Culicidae) larvae

Tohru Hayakawa, Naoya Yoneda, Kouji Okada, Ayuko Higaki, Mohammad Tofazzal Hossain Howlader, Toru Ide

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A 2,175-bp modified gene (cry11Ba-S1) encoding Cry11Ba from Bacillus thuringiensis subsp. jegathesan was designed and the recombinant protein was expressed as a fusion protein with glutathione S-transferase in Escherichia coli. The recombinant Cry11Ba was highly toxic against Culex pipiens mosquito larvae, being nine and 17 times more toxic than mosquitocidal Cry4Aa and Cry11Aa from Bacillus thuringiensis subsp. israelensis, respectively. Interestingly, a further increase in the toxicity of the recombinant Cry11Ba was achieved by mixing with Cry4Aa, but not with Cry11Aa. These findings suggested that Cry11Ba worked synergistically with Cry4Aa, but not with Cry11Aa, in exhibiting toxicity against C. pipiens larvae. On the other hand, the amount of Cry toxin bound to brush border membrane vesicles (BBMVs) did not significantly change between individual toxins and the toxin mixtures, suggesting that the increase in toxins binding to BBMVs was not a reason for the observed synergistic effect. It is generally accepted that synergism of toxins is a potentially powerful tool for enhancing insecticidal activity and managing Cry toxin resistance in mosquitoes. The mixture of Cry4Aa and Cry11Ba in order to increase toxicity would be very valuable in terms of mosquito control.

Original languageEnglish
Pages (from-to)61-68
Number of pages8
JournalApplied Entomology and Zoology
Volume52
Issue number1
DOIs
Publication statusPublished - Feb 1 2017

Keywords

  • Biological control
  • Cry toxin
  • Disease vector
  • Insect pest control
  • Synergistic toxicity

ASJC Scopus subject areas

  • Insect Science

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