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Identifier

000453693

Title

Διερεύνηση του μηχανισμού ανθεκτικότητας του δάκου της ελιάς, Bactrocera oleae, στο εντομοκτόνο spinosad και εναλλακτικές μέθοδοι αντιμετώπισης με βάση τα μικροβιακά βιοεντομοκτόνα

Alternative Title

Investigating the resistance mechanism of Bactrocera oleae to spinosad and alternative methods of control based on microbial bioinsecticides

Author

Μαστής, Στέφανος Μ

Thesis advisor

Βόντας, Ιωάννης

Reviewer

Σαρρής, Παναγιώτης
Χαλεπάκης, Γεώργιος

Abstract

The world of microorganisms still remains unexplored, with a plethora of metabolites with unique mechanisms of action, which could be used to solve a lot of problems in various fields. One of these, is the field of insecticide science, 5 with an obvious example being that of Spinosad, which is a mixture of two substances produced naturally by a species of streptomyces, and it is used to control populations of insects of medical or agricultural importance. Just like other insecticides, in recent years a rise in Spinosad resistance has been observed, in many species of insects, one of which is B.oleae. Recent studies associate the resistance, in species closely related to B.oleae, with mutations in the gene of the a6 subunit of the nAChR, which is the main target of Spinosad, that lead to truncated transcripts. In this study, an attempt was also made to connect the truncated transcripts of the a6 subunit, with the resistant phenotype of B.oleae individuals collected from different parts of Greece. Discovering the resistance mechanism behind this bacterial insecticidal substance, is not the only topic of this study, but finding new possible bioinsecticides is also one of its goals. More specifically, bacterial cells, bacterial supernatants, and streptomyces extracts, originating from bacteria that were able to inhibit the growth of other microorganisms, or proliferate in environments with harsh conditions, or both, were used in bioassays for the Culex pipiens molestus and Helicoverpa armigera species. These bioassays would allow, in preliminary testings, the discovery of possible insecticidal activities, but also activities that could affect the morphology, the physiology and the behavior of the insects. A bacterial supernatant originating from a Bacillus species, and an ethyl acetate streptomyces extract, were actually found to have an insecticidal activity against the larvae of Culex pipiens molestus species. These findings, blaze a trail for future studies, to shed their light on which substance or substances, and with what mechanism, lead to this phenotype.

Language

Greek

Subject

Bacillus

Culex pipiens molestus

Helicoverpa armigera

Insecticides

Streptomyces

Βάκιλος

Εντομοκτόνα

Στρεπτομύκητας

Issue date