Molecular Ecology (2001) 10, 525-533

A. Raps, J. Kehr, P. Gugerli, W.J. Moar, F. Bigler and A. Hilbeck (2001)
Immunological analysis of phloem sap of Bacillus thuringiensis corn and of the nontarget herbivore Rhopalosiphum padi (Homoptera: Aphididae) for the presence of Cry1Ab
Molecular Ecology 10 (2), 525-533
Abstract: Phloem sap of transgenic Bacillus thuringiensis (Bt) corn expressing a truncated form of the B. thuringiensis delta-endotoxin Cry1Ab, sap sucking aphids feeding on Bt corn and their honeydew were analysed for presence of Cry1Ab using ELISA. Phloem sap of Bt and non-Bt corn was collected using a newly developed technique with a microcapillary being directly inserted into the phloem tubes. Using this technique, no Cry1Ab was detected in the phloem sap. In contrast, measurable concentrations of Cry1Ab in the range of 1 ppb were detected when phloem sap of pooled leaf samples was extracted using EDTA buffer. This was probably because of Cry1Ab toxin released from damaged cells. When analysing apterous adults of Rhopalosiphum padi L. and their honeydew, no Cry1Ab could be detected. In contrast, Cry1Ab was clearly detected in both larvae of the leaf chewing herbivore Spodoptera littoralis (Boisduval) and their faeces, showing that Cry1Ab is detectable after ingestion and excretion by herbivores. These results suggest that R. padi ingests or contains no or only very low concentrations of Cry1Ab in the range of the detection limit. In consequence it is hypothesized that R. padi as an important prey for beneficial insects in corn is unlikely to cause any harm to its antagonists due to mediating Bt toxin.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): William J. Moar, Angelika Hilbeck

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
non-target effects/fate in environm.
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera littoralis	Maize/corn (Zea mays)
Bacillus thuringiensis genes in crops (entomopathogen)	Spodoptera littoralis
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Spodoptera littoralis