→ Project Reference: AGL2012-39965-C02-01/02

Summary

The enzyme succinate dehydrogenase (SDH) has become a promising molecular target to which attention has been paid by the most important agrochemical companies, as reflected by the fact that, out of the different fungicides developed in recent years, as many as 7 of them display inhibition of SDH as a mode of action. Among these new products, the fungicides fluopyram, fluxapyroxad and penthiopyrad are prominent. The use of these new pesticides, currently being introduced, will most likely become widespread in the coming years, making them potential chemical contaminants of horticultural products. In this context, rapid methods of analysis to complement the most common chromatographic-based methods will be of great help in ensuring the quality and safety of food.

It is particularly in this line that the main objective of the present research project has been focused. New rapid and user-friendly specific procedures, based on immunochemical methods, for the analysis of SDH fungicides in horticultural products have been developed. As a previous step in the development of these systems, it has been necessary to generate the corresponding immunoreagents (functionalized haptens, fungicide-protein conjugates and antibodies) specific for each of the three fungicides addressed in the project. By properly combining antibodies and assay conjugates, it has been possible to develop competitive ELISA-based methods capable of determining with high sensitivity (well below established maximum residue limits) and selectivity each of the target compounds in different foods (stone fruits, grapes, juices, and wine).

In addition, we have also carried out the evaluation of new nanomaterials as immunizing vehicles. For this purpose, immunogens have been prepared from multiple wall carbon nanotubes (MWNT) with different surface morphological characteristics and functionalized supeficially to enable the covalent attachment of protein-hapten conjugates or the haptens themselves. These constructs have been shown to be capable of triggering a secondary immune response equivalent in quality and quantity to that obtained with traditional conjugates, even employing doses of hapten up to 300 times lower than usual. In addition, it has been observed that immunization with MWNTs is safer for animals, and that these nanomaterials have some adjuvant character as long as their functionalization is performed with protein conjugates