Lack of detrimental effects of Bacillus thuringiensis Cry toxins on the insect predator Chrysoperla carnea: a toxicological, histopathological, and biochemical analysis

A. Rodrigo-Simón, R.A. de Maagd, C. Avilla, P.L. Bakker, J.W. Molthoff, J. González-Zamora, J. Ferré

    Research output: Contribution to journalArticleAcademicpeer-review

    79 Citations (Scopus)

    Abstract

    The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armigera larvae reared on Cry1Ac, Cry1Ab, or Cry2Ab toxins. In complementary experiments, a predetermined amount of purified Cry1Ac was directly fed to lacewing larvae. In both experiments no effects on prey utilization or fitness parameters were found. Since binding to the midgut is an indispensable step for toxicity of Cry proteins to known target insects, we hypothesized that specific binding of the Cry1A proteins should be found if the proteins were toxic to the green lacewing. In control experiments, Cry1Ac was detected bound to the midgut epithelium of intoxicated H. armigera larvae, and cell damage was observed. However, no binding or histopathological effects of the toxin were found in tissue sections of lacewing larvae. Similarly, Cry1Ab or Cry1Ac bound in a specific manner to brush border membrane vesicles from Spodoptera exigua but not to similar fractions from green lacewing larvae. The in vivo and in vitro binding results strongly suggest that the lacewing larval midgut lacks specific receptors for Cry1Ab or Cry1Ac. These results agree with those obtained in bioassays, and we concluded that the Cry toxins tested, even at concentrations higher than those expected in real-life situations, do not have a detrimental effect on the green lacewing when they are ingested either directly or through the prey
    Original languageEnglish
    Pages (from-to)1595-1603
    JournalApplied and Environmental Microbiology
    Volume72
    Issue number2
    DOIs
    Publication statusPublished - 2006

    Keywords

    • border membrane-vesicles
    • helicoverpa-armigera lepidoptera
    • resistant transgenic plants
    • maize expressing cry1ab
    • crystal proteins
    • spodoptera-exigua
    • binding-sites
    • larval midgut
    • noctuidae
    • toxicity

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