Studies of sustainable strategies to control phytopathogen agents

Calassanzio, Matteo (2020) Studies of sustainable strategies to control phytopathogen agents, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Scienze e tecnologie agrarie, ambientali e alimentari, 32 Ciclo. DOI 10.48676/unibo/amsdottorato/9411.
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Choosing natural enemies to suppress pest population has been for a long the key of biological control. Overtime the term biological control has also been applied to the use of suppressive soils, bio-disinfection and biopesticides. Biological control agents (BCA) and natural compounds, extracted or fermented from various sources, are the resources for containing phytopathogens. BCA can act through direct antagonism mechanisms or inducing hypovirulence of the pathogen. The first part of the thesis focused on mycoviruses infecting phytopathogenic fungi belonging to the genus Fusarium. The development of new approaches capable of faster dissecting the virome of filamentous fungi samples was performed. The semiconductor-based sequencer Ion Torrent™ and the nanopore-based sequencer MinION have been exploited to analyze DNA and RNA referable to viral genomes. Comparison with GeneBank accessions and sequence analysis allowed to identify more than 40 putative viral species, some of these mycovirus genera have been studied as inducers of hypovirulence in several phytopathogenic fungi, therefore future works will focus on the comparison of the morphology and physiology of the fungal strain infected and cured by the viruses identified and their possible use as a biocontrol agent. In a second part of the thesis the potential of botanical pesticides has been evaluated for the biocontrol of phloem limited phytopathogens such as phytoplasmas. The only active compounds able to control phytoplasmas are the antibiotic oxytetracyclines and in vitro direct and fast screening of new antimicrobials compounds on media is almost impossible due to the difficulty to culture phytoplasmas. For this reason, a simple and reliable screening method was developed to evaluate the effects of antimicrobials directly on phytoplasmas by an “ex-vivo” approach. Using scanning electron microscopy (SEM) in parallel with molecular tools (ddRT-PCR), the direct activity of tetracyclines on phytoplasma cells was verified, identifying also a promising compound showing similar activity.

Tipologia del documento
Tesi di dottorato
Calassanzio, Matteo
Dottorato di ricerca
Settore disciplinare
Settore concorsuale
Parole chiave
Biological control, phytoplasma, botanical pesticides, mycoviruses, hypovirulence.
Data di discussione
27 Marzo 2020

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