Chemical and phylogenetic aspects involved in the symbiosis between Amycolatopsis and attina ants

Author(s)

Camila Fiori Pereira

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
• Defense date: 2021-04-01

Examining board members

Monica Tallarico Pupo; Camila Carlos Shanley; Fernanda Oliveira das Chagas

• Advisor: Monica Tallarico Pupo

Abstract

Microorganisms stand out in the biosynthesis of biologically active secondary metabolites, and various organisms such as plants, insects, and animals have established symbiotic relationships with them throughout evolution. A well-studied example of this type of interaction is the symbiosis between ants of the Attina subtribe, the cultivar fungus (food fungus), the pathogenic fungus Escovopsis, and actinobacteria. Considering the genera of actinobacteria isolated from ants, little is known about the role of Amycolatopsis. Therefore, the current project contributed to the study of the metabolites produced by strains of Amycolatopsis spp. isolated from fungus-growing ants and also gave insights about the ecological role of this genus in the interaction. The screening was carried out by challenging 33 strains of Amycolatopsis against five different Escovopsis strains, and they showed good inhibition. The most promising strains were selected to be cultivated and extracted. Extracts were pre-purified by solid phase extraction, and the fractions were tested against Escovopsis to guide the study of active compounds. However, the extracts and fractions did not show antifungal activity against the pathogens. Different cultivation and extraction methodologies were carried out, and we also evaluated the inhibition by volatile compounds (VOCs) and siderophores. Amycolatopsis sp. ICBG609 inhibited the growth of the fungus Escovopsis sp. ICBG737 through the production of VOCs such as anisole. Fractions 100% and 75% MeOH of this strain showed a positive result in the chromeazurol S (CAS) assay, so they were analyzed in HRESI-MS. We identified the production of the compounds ECO-0501, a polyene polyketide, and coproporphyrins. Also, the genome analysis of ICBG609 confirmed the presence of the biosynthetic gene cluster (BGC) involved in the biosynthesis of the compound ECO-0501. Finally, the data of 16S rRNA and the complete genome of all strains of Amycolatopsis isolated by our research group were gathered, and phylogenetic analyses of these microorganisms were made. We observed a pattern of specificity between the association of the Amycolatopsis strains with ants, indicating that such strains may play an important ecological role in the interaction. (AU)

• FAPESP's process: 18/17502-2 - Natural products involved in the symbiosis between Amycolatopsis and attine ants
• Grantee: Camila Fiori Pereira
• Support Opportunities: Scholarships in Brazil - Master