Acquisition of Cry1Ac Protein by Non-Target Arthropods in Bt Soybean Fields

Abstract

Soybean tissue and arthropods were collected in Bt soybean fields in China at different times during the growing season to investigate the exposure of arthropods to the plant-produced Cry1Ac toxin and the transmission of the toxin within the food web. Samples from 52 arthropod species/taxa belonging to 42 families in 10 orders were analysed for their Cry1Ac content using enzyme-linked immunosorbent assay (ELISA). Among the 22 species/taxa for which three samples were analysed, toxin concentration was highest in the grasshopper Atractomorpha sinensis and represented about 50% of the concentration in soybean leaves. Other species/taxa did not contain detectable toxin or contained a concentration that was between 1 and 10% of that detected in leaves. These Cry1Ac-positive arthropods included a number of mesophyll-feeding Hemiptera, a cicadellid, a curculionid beetle and, among the predators, a thomisid spider and an unidentified predatory bug belonging to the Anthocoridae. Within an arthropod species/taxon, the Cry1Ac content sometimes varied between life stages (nymphs/larvae vs. adults) and sampling dates (before, during, and after flowering). Our study is the first to provide information on Cry1Ac-expression levels in soybean plants and Cry1Ac concentrations in non-target arthropods in Chinese soybean fields. The data will be useful for assessing the risk of non-target arthropod exposure to Cry1Ac in soybean.

Bt rice in China — focusing the nontarget risk assessment

“…Overall our data show a reduction in Cry protein concentrations from lower to higher trophic levels. This is in accordance with field studies from other Bt ‐transgenic crops producing different Cry proteins, including maize (Cry1Ab: Harwood et al ., ; Obrist et al ., ; Cry3Bb1: Meissle and Romeis, ), cotton (Cry1Ac: Torres et al ., ) and soybean (Cry1Ac: Yu et al ., ).…”

Farm‐scale evaluation of the impact of Cry1Ab Bt maize on canopy nontarget arthropods: a 3‐year study

“…Thus, the toxin Cry3Bb1 (event MON88017) was found in Z. scutellaris and Empoasca pteridis Göethe (Hemiptera: Cicadellidae) at rates of 1.2 and 0.8 μg Cry3Bb1/g of dry weight, respectively, representing 0.5% and 0.3% of the Cry3Bb1 toxin present in maize plant (Meissle & Romeis, ). Similarly, when toxin Cry1Ac was measured on nymphs of Cicadella viridis L. (Homoptera: Cicadellidae) collected in Bt soybeans fields, the amount of toxin detected was 1.3 μg Cry1Ac/g of dry weight, that is the 3.5% of the toxin present in the plant (Yu et al ., ). We found no detectable levels of the toxin in the cicadellid Macrosteles spp.…”

Responses of two ladybird beetle species (Coleoptera: Coccinellidae) to dietary RNAi

“…As a result, ladybird beetles may be exposed to molecules produced by GE plants directly via consumption of pollen or indirectly via consumption of herbivores, which feed on the plant. That ladybird beetles ingest insecticidal compounds produced in GE plants has been documented in several field studies with Bt ‐transgenic crops . In the case of GE maize plants producing dsRNA targeting D. v. virgifera , ladybird beetles are particularly suitable test species to inform the non‐target risk assessment because they belong to the same insect order.…”

“…That ladybird beetles ingest insecticidal compounds produced in GE plants has been documented in several field studies with Bt-transgenic crops. [44][45][46][47][48] In the case of GE maize plants producing dsRNA targeting D. v. virgifera, ladybird beetles are particularly suitable test species to inform the non-target risk assessment because they belong to the same insect order. Furthermore, Coleoptera in general show a significantly greater sensitivity to dietary dsRNA than other insect orders.…”