The death is red: analysis of the predicted secretome of Aspergillus welwitschiae, with emphasis in pathogenicity and carbohydrate metabolism

• Autor(a) principal: Gabriel Quintanilha Peixoto
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/41331
• topic: Fungo; Podridão Vermelha; Interação Planta-Patógeno.; Bioinformática; Fungos; Aspergillus - patogenicidade; Interações Hospedeiro-Patógeno

In 2018, Aspergillus welwitschiae was described as the causing agent of the bole rot disease of sisal (Agave sisalana), rather than Aspergillus niger as previously thought, of which A. welwitschiae is a cryptic species. Since then, we have sought to understand the mechanisms of pathogenicity of this fungus by sequencing the genome of two isolates from A. sisalana infected stem tissues and subsequent analysis of the gene content of these fungi. The genomes sequenced in Illumina HiSeq 2500 were assembled and annotated, possessing approximately 34.8 Mbp containing 12,549 protein-coding genes and 32.2 Mbp containing 11,809 protein-coding genes for CCMB663 and CCMB674, respectively. The resulting files were used for the analysis of secretomes, in which different software were applied as filters to select the secreted proteins for the extracellular medium, and these proteins were associated with terms of Gene Ontology (GO). Our results show that there are a number of terms that describe functions associated with the degradation of proteins, lipids, and especially carbohydrates and that the relative abundance of these terms is similar between different isolates. From this set of proteins predicted as secreted, possible effector proteins were identified, that is, proteins that facilitate the invasion and colonization of the infected plant. Our results show that most of the proteins identified have no similarity with known effectors, and in those where it was possible to identify conserved domains, there are essential and very important genes for virulence in plants, which can act both to silence the immune response and to stimulate it, which can cause cell death in plant tissues. Secretory and cytosolic plant cell wall degrading enzymes were also analyzed. There is a great diversity of genes encoding cell wall degrading enzymes, some specialized in the degradation of sugars present in large quantities in the tissues of the sisal stem, as well as degradation proteins that also act as effectors. With our results, we have improved the understanding of the Aspergillus welwitschiae x Agave sisalana pathosystem, and also identified new effectors of interest in the fungus-plant interaction.