Combining modern methods of mass spectrometry and genome mining for the analysis of interactions between symbiotic microorganisms from Trachymyrmex colonies

Abstract

Attine ants have as a behavioral feature, the cultivation of "fungal gardens" for nutritional purposes. However, the integrity of the colonies can be compromised when the growth of Escovopsis fungus is observed, which is a specialized parasite of these gardens. One of the strategies to protect colonies is the establishment of a symbiotic relationship with actinobacteria, mainly of the genus Pseudonocardia, which produce chemical defenses. This project proposes a systematic study of the metabolic profiles from symbiotic Pseudonocardia and Escovopsis, isolated from Amazonian Trachymyrmex ants. Microorganisms associated with social insects have been extensively studied as sources of new chemical structures with antimicrobial activity, with high potential for clinical uses that may still provide ecological insights about the system. However, there are no studies in the literature revealing the metabolites produced by Pseudonocardia during the interaction with the specific pathogen of the colony (Escovopsis), their selectivity and ecological roles. 39 Pseudonocardia strains isolated from Trachymyrmex ants and two Escovopsis (from colonies of Trachymyrmex and Acromyrmex ants) were collected in the Brazilian Amazon biome. The genomes of 22 Pseudonocardia have been completely sequenced. Many genes encoding known antibiotic-producing enzymes have been identified, as well as genes that could potentially be involved in the biosynthesis of unknown metabolites, revealing a high unexplored chemical2potential. Pseudonocardia isolates were tested against two Escovopsis strains and the chemical profiles obtained from the extracts of the cultures are being analyzed using recent tandem mass spectrometry approaches (the GNPS platform and in silico tools) associated with genome mining, to understand the chemistry involved in the interaction between these microorganisms. The inspection of different patterns, according to the production of metabolites in the molecular networks, also allows to select some Pseudonocardia strains with outlier chemical profiles that will be prioritized for isolation of compounds. In addition, the analysis of this large number of Pseudonocardia strains in a biome, never performed before, will make the study more robust, allowing a better understanding of the relationship between phylogeny and metabolomic content, and the possible evolutionary significance of this association. The products isolated and identified will be associated with their putative Biosynthetic Gene Clusters (BGCs) and tested against Escovopsis and "fungal garden" for correlation of selectivity and ecological function. (AU)