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Impact and fate of pesticidal proteins from bacillus thuringiensis spp in tropical soils and waters as influenced by interactions with clays

Objective

The main objectives are defined as follows :
* To determine the potential for the use of clays as an agent by which to introduce into selected target environments biopesticidal toxins derived from Bacillus thuringiensis, for protecting crops against various pests and for control of vector-borne disease, such as malaria.
* To evaluate the effectiveness, persistence and impact of such biomolecules on the environment where they are adsorbed on pure clays and soil mineral colloids.
* To evaluate the potential effects that the introduction of transgenic organisms which contain genes coded for these pesticidal toxins may have in tropical soil and aquatic environments.
Expected Outcome

The project should allow to understand the mechanisms of adsorption and binding of the pesticidal toxins from BT spp. on clay minerals and other particles and the effects of such surface interactions on the persistence and pesticidal activity of these toxins in soils and waters, and to evaluate the potential effects in some tropical soils and waters of the release of pesticidal toxins from plants genetically modified to code for these toxins.
On this basis, the most effective and environmentally compatible way to present these active biomolecules to their target organisms e.g. disease vectors, such as mosquitoes) will be established.
The key activities involve :
* The study of both the efficacy of proteinic toxins molecules associated with Bacillus thuringiensis (BT) as environmentally acceptable biopesticides, and their persistence or degradation in tropical soils and waters.
* In order to establish the potential of clays as carriers of the toxins, initial investigations will be carried out on pure commercial clays as the basis for a model of the interaction between the toxins and different clays minerals. Thereafter, studies on clays extracted from actual soils, by non-destructive techniques, will be used as the basis for the development of a model to illustrate what is likely to happen in the less pure natural soil environment.
* Initially, the main target species will be insects that are important as pests of agricultural crops. Equally, with regard to human health, the main target species will be the mosquitoes, whose larvae breed and mature in water and, therefore, the efficacy of the toxins in aquatic environments will be tested.
* A comparison will be done between uncomplexed toxins (free toxins) and those that are bound to clays, in order to evaluate the contribution of clays to the general dynamics of the toxins.
* The impact of the introduction of such materials on the environment will be evaluated by monitoring, in the soil, the fate of toxins produced by Bt as well as these of transgenic plant materials into which the toxin genes have been introduced.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL RESEARCH COUNCIL OF ITALY
Address
15,Piazzale Delle Cascine 28
50144 Firenze
Italy

Participants (5)

CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain
Address
115,Calle Serrano 115 Bis
28006 Madrid
Institut National de la Recherche Agronomique
France
Address
Route De Saint-cyr
78026 Versailles
SOKOINE UNIVERSITY OF AGRICULTURE
Tanzania
Address

Morogoro
UNIVERSITY OF FORT HARE
South Africa
Address

5700 Alice
UNIVERSITY OF ZIMBABWE
Zimbabwe
Address
Mount Pleasant
30 Harare