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INCREASE IN LARVAL GUT PROTEOLYTIC ACTIVITIES AND Bti RESISTANCE IN THE DENGUE FEVER MOSQUITO
Author(s) -
Tetreau Guillaume,
Stalinski Renaud,
David JeanPhilippe,
Després Laurence
Publication year - 2013
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21076
Subject(s) - bacillus thuringiensis , aedes aegypti , biology , dengue virus , dengue fever , microbiology and biotechnology , strain (injury) , aedes , mosquito control , virology , larva , bacteria , immunology , ecology , malaria , genetics , anatomy
The bioinsecticide Bacillus thuringiensis var. israelensis (Bti) is increasingly used worldwide for mosquito control. Although no established resistance to Bti has been described in the field so far, a resistant Aedes aegypti strain (LiTOX strain) was selected in the laboratory using field‐collected leaf litter containing Bti toxins. This selected strain exhibits a moderate resistance level to Bti, but a high resistance level to individual Cry toxins. As Bti contains four different toxins, generalist resistance mechanisms affecting mosquito tolerance to different toxins were expected in the resistant strain. In the present work, we show that the resistant strain exhibits an increase of various gut proteolytic activities including trypsins, leucine‐aminopeptidases, and carboxypeptidase A activities. These elevated proteolytic activities resulted in a faster activation of Cry4Aa protoxins while Cry4Ba or Cry11Aa were not affected. These results suggest that changes in proteolytic activities may contribute to Bti resistance in mosquitoes together with other mechanisms.