Analysis of natural products involved in the interactions between Pseudonocardia and Escovopsis associated with Trachymyrmex ants using molecular networking

Abstract

The ants of the Attini tribe have developed over time a relationship of domestication and later mutualism with Basidiomycete fungi, which are grown in fungal gardens and serve as the main food source of these ants. Several microorganisms can parasitize the colonies of these farmer insects, and the ants have created physical and chemical defense mechanisms against these invaders. However, these mechanisms are ineffective against parasitic fungi of the genus Escovopsis. Thus, attines associated themselves with an actinobacteria that produces substances with antimicrobial activity against these parasites. Pseudonocardia is one of the most commonly found actinobacteria associated with the body structures of the attines, which have adapted to shelter and protect these symbiotic microorganisms. The natural products produced by these bacteria in this type of interaction are still poorly explored and may have promising antibiotic activities for the planning new drugs, since actinobacteria are the source of most antibiotics available on the market. The ants of the genus Trachymyrmex represent an important point of transition between the basal ants and the upper ants, and are considered the key group for the understanding of phylogenetic relationships in the evolution of the Attini tribe. Recently, 39 Pseudonocardia strains were isolated from Trachymyrmex colonies collected in the Amazon, as part of the international cooperation thematic project FAPESP/FIC-NIH (2013/50954-0). The genomes of 15 Pseudonocardia strains were completely sequenced and initial analyzes of the genomes demonstrated the presence of known antibiotic producing genes and genes that potentially encode new metabolites. Hence, this project aims to conduct a detailed study on the chemical interactions that occur between the fungus parasite Escovopsis and different Pseudonocardia strains isolated from ants of the genus Trachymyrmex, by using the state of the art of mass spectrometry and genomic analysis methods. The vast amount of mass spectrometry data will be organized in the form of a molecular network, using the newly created online GNPS platform - The Global Natural Products Social Molecular Networking. Genome analysis, or genome mining, will be performed using the antiSMASH, RAST and MultiGeneBlast platforms. The combination of these metabolomics and genomics tools will allow the rapid identification of known compounds and potentially active new compounds produced in the bacterium-fungus interactions.