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Master of Science




Dr. Abdelali Hannoufa


Carotenoid cleavage dioxygenases (CCDs) are responsible for the cleavage of carotenoids into smaller compounds, including apocarotenoids. The volatile apocarotenoids produced have demonstrated a repellent and feeding deterrent effect with some insects. To understand the formation of apocarotenoids and the effect on insect oviposition and feeding preference, I investigated the role of CCD genes in plant-insect interactions by comparing four different transgenic genotypes that over-express CCD and the respective wild-type (WT) for two model plants. CCD4 and CCD1 genes were overexpressed in Arabidopsis thaliana (Arabidopsis) and LeCCD1-1 and LeCCD1-2 genes were overexpressed in Solanum lycopersicum (tomato), Oviposition choice bioassays with the cabbage looper moth (Trichoplusia ni) and greenhouse whitefly (Trialeurodes vaporariorum) showed a significantly greater oviposition of both insects on the transgenic plants in comparison to WT plants, whereas feeding assays with T. ni larvae indicated no preference toward CCD over-expressing plants. The findings suggest that manipulating the carotenoid-based volatile profile of plants could provide a novel strategy to attract pest insects away from the crops towards these trap plants. This would also contribute to a reduction in the dependence of chemical pesticides and reduce the associate negative environmental effects of their use.

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