A screening method for prioritizing non-target invertebrates for improved biosafety testing of transgenic crops

Abstract

We have developed a screening method that can be used during the problem formulation phase of risk assessment to identify and prioritize non-target invertebrates for risk analysis with any transgenic plant. In previously published protocols for this task, five criteria predominated. These criteria have been combined by our method in a simple model which assesses: (1) the possible level of risk presented by the plant to each invertebrate species (through measurements of potential hazard and exposure, the two principal criteria); (2) the hypothetical environmental impact of this risk (determined by the currently known status of the species' population in the ecosystem and its potential resilience to environmental perturbations); (3) the estimated economic, social and cultural value of each species; and (4) the assessed ability to conduct tests with the species. The screening method uses information on each of these criteria entered into a specially designed database that was developed using Microsoft Access 2003. The database holds biological and ecological information for each non-target species, as well as information about the transgenic plant that is the subject of the risk assessment procedure. Each piece of information is then ranked on the basis of the value of the information to each criterion being measured. This ranking system is flexible, allowing the method to be easily adapted for use in any agro-ecosystem and with any plant modification. A model is then used to produce a Priority Ranking of Non-Target Invertebrates (PRONTI) score for each species, which in turn allows the species to be prioritized for risk assessment. As an example, the method was used to prioritize non-target invertebrates for risk assessment of a hypothetical introduction of Bacillus thuringiensis (Bt) Cry1Ac-expressing Pinus radiata trees into New Zealand.

Developing risk hypotheses and selecting species for assessing non-target impacts of GM trees with novel traits: The case of altered-lignin pine trees

“…The Eco Invertebase is a database of biological and ecological information on New Zealand invertebrate species developed using Microsoft® Access 2003 as described by Todd et al (2008). For the present study, egg-laying and shelter-building behaviour and sites were added to the receptor attributes listed in Appendix 1 of Todd et al (2008).…”

“…Table 3 presents part of a list of invertebrate species and their priority rankings ("RankF") based on their likelihood of being affected and thus their potential as suitable subjects for testing risk hypotheses involving invertebrates for altered-lignin GM pine under New Zealand conditions. The list was produced by modifying the PRONTI (Priority Ranking of Non-Target Invertebrates) model (Todd et al, 2008) and applying it to a database containing biological and ecological information on over 1300 New Zealand invertebrate species found in productive ecosystems (hereafter referred to as the Eco Invertebase).…”

“…Further separation of species was achieved by applying additional selection criteria, as in Todd et al (2008). New Zealand environmental protection legislation explicitly mentions preservation of native species and valued exotic species, and species of significance to indigenous people, reflecting some unique aspects of New Zealand's biota, agriculture, and culture.…”

“…The original PRONTI model (Todd et al, 2008) was developed for a GM Bt plant application and has been adapted for other traits with obvious hazards or benefits for invertebrates (B.I.P. Barratt, pers.…”

“…A set of risk hypotheses describing predicted relationships between altered-lignin GM pine and potentially affected organisms was then developed. Lists of species, ranked in order of suitability as potential test subjects, were then produced by applying a screening model (adapted from Todd et al (2008)) to a database of 251 invertebrates known to occur in New Zealand pine plantations. Some recommendations for experiments to measure the potential non-target impacts of altered-lignin GM pines are presented.…”