caa a22 4500 605502803 CHVBK 20210128100607.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00253-015-6655-5 doi (NATIONALLICENCE)springer-10.1007/s00253-015-6655-5 Fate of the insecticidal Cry1Ab protein of GM crops in two agricultural soils as revealed by 14C-tracer studies [Elektronische Daten] [Petra Valldor, Rona Miethling-Graff, Rainer Martens, Christoph Tebbe] Insecticidal delta-endotoxins of Bacillus thuringiensis are among the most abundant recombinant proteins released by genetically modified (GM) crops into agricultural soils worldwide. However, there is still controversy about their degradation and accumulation in soils. In this study, 14C-labelled Cry1Ab protein was applied to soil microcosms at two concentrations (14 and 50μgg−1 soil) to quantify the mineralization of Cry1Ab, its incorporation into the soil microbial biomass, and its persistence in two soils which strongly differed in their texture but not in silt or pH. Furthermore, ELISA was used to quantify Cry1Ab and its potential immunoreactive breakdown products in aqueous soil extracts. In both soils, 14CO2-production was initially very high and then declined during a total monitoring period of up to 135days. A total of 16 to 23% of the 14C activity was incorporated after 29 to 37days into the soil microbial biomass, indicating that Cry1Ab protein was utilized by microorganisms as a growth substrate. Adsorption in the clay-rich soil was the most important factor limiting microbial degradation; as indicated by higher degradation rates in the more sandy soil, extremely low concentrations of immunoreactive Cry1Ab molecules in the soils' aqueous extracts and a higher amount of 14C activity bound to the soil with more clay. Ecological risk assessments of Bt-crops should therefore consider that the very low concentrations of extractable Cry1Ab do not reflect the actual elimination of the protein from soils but that, on the other hand, desorbed proteins mineralize quickly due to efficient microbial degradation. Springer-Verlag Berlin Heidelberg, 2015 Protein degradation nationallicence Cry proteins nationallicence Bt-toxin nationallicence Bt-maize nationallicence Cry1Ab nationallicence Genetically modified plants nationallicence Environmental risk assessment nationallicence Soil microbial biomass nationallicence 14C-labelled compounds nationallicence Soil microbiology nationallicence Valldor Petra Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut Miethling-Graff Rona Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut Martens Rainer Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut Tebbe Christoph Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/17(2015-09-01), 7333-7341 0175-7598 99:17<7333 2015 99 253 https://doi.org/10.1007/s00253-015-6655-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00253-015-6655-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Valldor Petra Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Miethling-Graff Rona Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Martens Rainer Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut NATIONALLICENCE 700 1- Tebbe Christoph Thünen-Institut für Biodiversität, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei, Bundesallee 50, 38116, Braunschweig, Germany aut NATIONALLICENCE 773 0- Applied Microbiology and Biotechnology Springer Berlin Heidelberg 99/17(2015-09-01), 7333-7341 0175-7598 99:17<7333 2015 99 253