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Speakers - Paulo C. Vieira

Short Lecture

 

CHEMISTRY AND ECOLOGY OF ESCOPSIS WEBERI AND MICROORGANISMS ASSOCIATED WITH LEAF-CUTTING ANTS

 

Ana Carolina A. dos Santos 1, Kirstin Scherlach 2, Paulo C. Vieira 1*, Christian Hertweck 2

 

1  Department of Chemistry, Federal University of Sao Carlos, Sao Carlos, Brazil

2  Leibniz Institute for Natural Product Research and Infection Biology, HKI, Beutenbergstraße 11a, 07745 Jena, Germany

* Correspondence: dpcv@ufscar.br

 

The study of microorganisms associated with insects provides unique opportunities to exploit natural antimicrobial and insecticides agents due to the chemical mediators utilized in the defensive and threat strategies. Leaf-cutting ants’ fungal garden comprises a complex symbiosis in which are involved, at least, a mutualistic fungus (Leucoagaricus gongylophorus), a specialized parasite (Escovopsis spp.), symbiont actinomycetes (Pseudonocardia and Streptomyces spp.) and other microorganisms with unknown ecology relationship. Fungi belonging to the genus Escovopsis are mycoparasites of the ants' fungal gardens and can destroy fungal gardens completely by the secretion of antifungal and antibacterial metabolites. Moreover, it is already known that E. weberi has a reduced genome in which were identified 17 putative secondary metabolite biosynthesis clusters like terpene synthases, polyketide synthases (PKS) and nonribosomal peptide synthases (NRPSs) (Man, 2016). However, the basis of this interaction remains unknown. Therefore, leaf-cutting ants microbiome comprises an ideal system to study the chemical-ecology of microbial interactions due to the wealth of microbial interactions described, and the lack of information on the molecules involved therein. Aiming to get some progress in the chemical-ecology of E. weberi, especially in its mode of action, we have performed some coculture and MALDI imaging experiments. These experiments revealed that E. weberi produces some nitrogenated compounds as virulence factors that target the mutualist Pseudonocardia. As the population of bacteria decreases with the secretion of these substances, the nest become more susceptible to the attack of E. weberi. Based on the obtained results, we hypothesize that these metabolites play an important role during the infection process and consequently, in the nest collapse.