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Fate of insecticidal Bacillus thuringiensis Cry protein in soil: differences between purified toxin and biopesticide formulation
Author(s) -
Hung Truong Phuc,
Truong Le Van,
Binh Ngo Dinh,
Frutos Roger,
Quiquampoix Hervé,
Staunton Siobhán
Publication year - 2016
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4262
Subject(s) - biopesticide , bacillus thuringiensis , biology , germination , cry1ac , endospore , pesticide , bacillaceae , spore , food science , botany , genetically modified crops , agronomy , biochemistry , bacillus subtilis , bacteria , genetics , transgene , gene
BACKGROUND Bacillus thuringiensis produces insecticidal proteins known as Cry, and its efficiency and absence of side effects make it the most widely used biopesticide. There is little information on the role of soils in the fate of Cry proteins from commercial biopesticide formulations, unlike toxins from genetically modified crops, which have been intensively studied in recent years. The persistence of Cry in soil was followed under field and laboratory conditions. RESULTS Sunlight accelerated loss of detectable Cry under laboratory conditions, but little effect of shade was observed under field conditions. The half‐life of biopesticide proteins in soil under natural conditions was about 1 week. Strong temperature effects were observed, but they differed for biopesticide and purified protein, indicating different limiting steps. CONCLUSION For the biopesticide, the observed decline in detectable protein was due to biological factors, possibly including the germination of B. thuringiensis spores, and was favoured by higher temperature. In contrast, for purified proteins, the decline in detectable protein was slower at low temperature, probably because the conformational changes of the soil‐adsorbed protein, which cause fixation and hence reduced extraction efficiency, are temperature dependent. © 2016 Society of Chemical Industry