Caracterização das interações químicas entre os microrganismos simbiontes das formigas cortadeiras

Abstract

The complex symbiosis in Attini ant nests inspires curiosity in different fields of research from Microbiology to Chemical Ecology. These ants cultivate their mutualist fungus for approximately 50 million years in structures well-known as fungi gardens. Attini ants need their mutualist fungus to get nutrients and essential enzymes for feeding. Other microorganisms, such as actinobacteria, produce antibiotics, which help to protect the ants against parasites, as the Escovopsis genus, that harm the whole nest. One of which important systems of agriculture in the Attine group is the leaf-cutting ants, of genus Atta and Acromyrmex, which cultivate only a specific species of fungus, Leucoagaricus gongylophorus, each one does not survive without the ants' mutualism. They are known as leaf-cutting ants due to their ability in cutting fresh leaves to cultivate the fungus and they have been characterized as an agricultural pest in Pinus and Eucalyptus forests. The new black yeast discovery in leaf-cutting ants cuticle was important to instigate studies on the chemical-ecological relationship upon other symbionts. Hence, this study aims to use different analytical tools to understand the chemical interactions between the leaf-cutting ants' symbiont microbes. The thesis was divided into three main parts: A) an approach over the co-cultures among different symbiont microbes, focusing on different methodologies; B) multivariate data analysis, molecular networking, mass spectrometry imaging, and biological assays about the ecological interaction of black yeast and parasite co-culture; C) an ecological function investigation of black yeast metabolites correlated to the antimicrobial activity in opposition to the actinobacteria. The findings of this work contribute with relevant information about the microbial interactions existing in leaf-cutting ant nests related to the black yeast, which was reported here for the first time. Nevertheless, next step experiments regarding the black yeasts have been showing promise in understanding more about this microbial complexity.