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Identifier 000369240
Title Γενετική και μοριακή ανάλυση της ανθεκτικότητας του τετρανύχου, Tetranychus urticae (Acari : Tetranychidae) στις αβερμεκτίνες
Alternative Title Genetics and molecular analysis of resistance in the two-spotted spider mite Tetranychus urticae (Acari : Tetranychidae) in avermectins
Author Ρήγα, Μαρία
Thesis advisor Βόντας, Ιωάννης
Abstract The two spotted spider mite (TSSM), Tetranychus urticae (Koch) (Acari : Tetranychidae) is one of the most important pests in many agricultural crops worldwide. This species becomes highly resistant in many of the commercial compounds which are used for its control. An avermectin resistant strain of T. urticae (TU82) that was isolated from a heavily sprayed rose plant greenhouse near Athens (Marathonas) and had high levels of resistance against avermectins (2000 fold:.2000-fold higher dose was needed in order to kill 50% of TU82 mites, compared to susceptible strain). Avermectins belong to the class of macrocyclic lactones and are derived from the fermentation of the microorganism Streptomyces avermitillis. The target site of these compounds is GABA and glutamate – gated chloride channels. Two point mutations in glutamate - gated chloride channels have been associated with avermectin resistance, one previously characterized and another one that has been more recently found in our lab but not yet characterised. I used genetic crosses in order to, (a) study the dominance of the avermectin resistance phenotype of TU82, (b) investigate the number of genes involved in the resistance and (c) investigate the role of the novel mutation in resistance. The results showed that the mode of inheritance is intermediate and resistance is controlled by more than one gene. Furthermore, the second point mutation seems to play an important role on the phenotype of resistance to avermectins. Finally, we developed a RNA interference method for the functional validation of the role of specific genes in T. urticae non target site resistance. The dsRNA was introduced into the organisms via micro-injections and it successfully silenced the AChE gene when the injections were done to synchronous (same age) mites by applying double injections.
Language Greek
Subject AChE
Point mutations
Issue date 2011-11-18
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
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