Characterization of the Spectrum of Insecticidal Activity for IPD072Aa: A Protein Derived from Psuedomonas chlororaphis with Activity Against Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Abstract

Western corn rootworm ( Diabrotica virgifera virgifera LeConte) presents significant pest management challenges for farmers in both North America and Europe. IPD072Aa, a protein derived from Pseudomonas chlororaphis , has previously been shown to have activity against western corn rootworm. In the current study, the spectrum of activity of IPD072Aa was evaluated in controlled laboratory diet bioassays. IPD072Aa was fed at high concentrations in subchronic or chronic bioassays to 11 different insect species, representing 4 families within Coleoptera, and an additional 4 species representing four families of Lepidoptera. No adverse effects were noted in the Lepidoptera species. Within the order Coleoptera, western corn rootworm was the most sensitive species tested. A range of responses was observed within each of the four families of Coleoptera evaluated that included either no-observed effects or reduced growth, developmental delays, and/or reduced survival. These data will help inform the environmental risk assessment of genetically modified plants that express the IPD072Aa protein for western corn rootworm control.

Sublethal Endpoints in Non-target Organism Testing for Insect-Active GE Crops

“…One example of a non-Bt insecticidal protein that has been subject to extensive NTO assessment is IPD072Aa, isolated from Pseudomonas chlororaphis, which has activity against WCR (Schellenberger et al, 2016). The IPD072Aa protein has been the subject of bioassays to determine the spectrum of activity in order to inform the NTO risk assessment (Boeckman et al, 2019). As the target pest is a coleopteran, bioassays were conducted with 11 species of Coleoptera, representing four families.…”

“…No observed effects were reported for any of the Lepidoptera species, but both mortality and sublethal effects were observed at varying protein concentrations in some of the tested Coleoptera. In line with best practices for NTO study design (see NTO Study Design above) the criteria for selection of species to characterize the spectrum of activity of IPD072Aa was based on several factors such as the phylogenetic relationship between the species and WCR, established laboratory bioassay methodologies, availability of laboratory reared insects, a known suitable diet and reproducibility of the measurement endpoints (Boeckman et al, 2019).…”

“…Whenever possible, however, mechanisms should be encouraged to improve access to this type of information. There are several recent examples where early characterization of pesticidal molecules have been published (Bachman et al, 2013(Bachman et al, , 2017Boeckman et al, 2019). However, the research community is encouraged to find new means of storing and disseminating information that often is omitted from peerreviewed publications but has value as a collective resource in further development of NTO risk assessment methodology.…”

Agronomic and compositional assessment of genetically modified DP23211 maize for corn rootworm control

“…The PAT and PMI proteins have a history of safe use in agriculture, 20,[39][40][41] and are present in a number of approved events that are currently in commercial use. Based on the history of safe use of the PAT and PMI proteins in agriculture, 20,[39][40][41] and based on the mode of action and specificity of activity of DvSSJ1 dsRNA and IPD072Aa protein, [14][15][16][17][18] there was no a priori reason to expect the introduced traits would interact with plant metabolic pathways in such a way as to change the composition. The composition results from this study are in line with results generated from over 25 years GM crop cultivation, which have not identified any biologically relevant changes in composition that are associated with the development of a GM plant.…”

“…The IPD072Aa protein has been shown to be specific, with activity limited to within the order Coleoptera. 14 , 17 , 18 The ipd072Aa gene is derived from Pseudomonas chlororaphis , 14 a naturally occurring, ubiquitous bacterium found in the environment that lacks known allergenic or toxic properties and has a history of safe use in agriculture. 19 DP23211 maize plants contain the phosphinothricin acetyltransferase (PAT) protein, 20 encoded by the mo-pat gene, which confers tolerance to the herbicidal active ingredient glufosinate ammonium at current labeled rates.…”