Effect of water-deficit stress on cotton plants expressing the Bacillus thuringiensis toxin

Martins C.M., Beyene G., Hofs Jean-Luc, Krüger K., Van der Vyver C., Schlüter U., Kunert K.. 2008. Effect of water-deficit stress on cotton plants expressing the Bacillus thuringiensis toxin. Annals of Applied Biology, 152 (2) : 255-262.

Résumé : Bacillus thuringiensis (Bt) crops require a high dosage of Bt toxin to delay development of insect resistance, in particular, when the refuge strategy is applied. This strategy is threatened by plant developmental and environmental factors that might reduce Bt toxin concentration and Bt efficacy in Bt crops. Growth of Bt (Cry1Ac) cotton under prolonged, moderate water deficit as a single stress factor was evaluated. Bt cotton plants were analysed for physiological performance, Bt toxin concentration and Bt efficacy. For performance analysis, leaf and total plant dry weight and leaf area were measured. Bt toxin concentration was determined by an immuno-assay. Effects of Bt toxin on growth and mortality of African cotton bollworm, Helicoverpa armigera, larvae were measured in different plant organs. Leaves from young plants exposed for 30 days to moderate water deficit had both higher Bt toxin concentrations and were more effective against larvae than leaves, flowers or bolls from mature flowering plants exposed to 60 days of moderate water deficit. Although growth of Bt cotton plants under moderate water-deficit conditions decreased Bt concentrations in leaves, flowers and bolls, this had no effect on efficacy against first-instar cotton bollworm larvae. No significant evidence was found that moderate water deficit, as a single stress factor, decreases Bt efficacy in Bt cotton.

Mots-clés Agrovoc : Gossypium, Bacillus thuringiensis, Helicoverpa armigera, plante transgénique, résistance aux organismes nuisibles, déficit d'humidité du sol, stress dû à la sécheresse, physiologie végétale, toxine bactérienne, pesticide bactérien

Mots-clés complémentaires : Coton Bt

Classification Agris : H10 - Ravageurs des plantes
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Martins C.M., Eduardo Mondlane University (MOZ)
• Beyene G., University of Pretoria (ZAF)
• Hofs Jean-Luc, CIRAD-PERSYST-UPR Systèmes cotonniers (BEL)
• Krüger K., University of Pretoria (ZAF)
• Van der Vyver C., Stellenbosch University (ZAF)
• Schlüter U., University of Pretoria (ZAF)
• Kunert K., University of Pretoria (ZAF)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/544376/)

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