The virome of sisal (Agave spp.) and genomics aspects of its main pathogen, Aspergillus welwitschiae (Ascomycota, Trichocomaceae)

• Autor(a) principal: Gabriel Quintanilha Peixoto
• Data de Publicação: 2023
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/58455
• topic: Virus; Red rot of sisal; Plant-pathogen interaction; Evolution; Susceptibility; Bioinformática; Sisal; Vírus; Aspergillus

This thesis examines diverse aspects impacting sisal cultivation in Brazil, with a particular focus on exploring the virome (viral species content) of the three main sisal varieties found in the fields. Additionally, it investigates various genomic facets of sisal's primary pathogen, Aspergillus welwitschiae, potentially linked to the progression of the bole rot disease. Utilizing an RNA-Seq-based approach, the study provides a comprehensive characterization of the virome associated with Agave sisalana (the main cultivated sisal variety), Agave fourcroydes, and Agave Hybrid 11648, two less cultivated varieties supposedly exhibiting higher resistance to bole rot disease. A noteworthy finding includes the identification of twenty-five (25) viral species, including the Cowpea Mild Mottle Virus (CPMMV), with roots demonstrating a particularly diverse and rich plant tissue attributed to plant-fungi associations. Furthermore, the research outlines the phylogenetic relationships of A. welwitschiae within the Nigri section of the Aspergillus genus, highlighting evolutionary traits impacting genes that may influence the establishment and progression of sisal's bole rot. The discovery that A. welwitschiae is polyphyletic (lacking a single common ancestor) and the identification of genes in primary and secondary metabolism under diversifying selection add new insights to the field. The thesis also includes the development of a patent based on the orthology analysis conducted in Chapter II, revealing a unique region in the gene coding for Δ1-pyrroline-5-carboxylate reductase (PC5R) specific to A. welwitschiae, despite its polyphyletic nature. The study further investigates the pathogenicity of A. welwitschiae by examining its secondary metabolism and potential roles in disease progression through wet-bench and in silico techniques. Notably, high-performance liquid chromatography revealed various metabolites, including those typical of fungi's primary and secondary metabolism. Lastly, the thesis presents a comprehensive discussion and concluding remarks, integrating findings from all previous chapters and outlining future research perspectives in this domain.