title: Nature of the interactions between hypocrealean fungi and the mutualistic fungus of leaf-cutter ants.
abstract: Leaf-cutter ants cultivate and feed on the mutualistic fungus, Leucoagaricus gongylophorus, which is threatened by parasitic fungi of the genus Escovopsis. The mechanism of Escovopsis parasitism is poorly understood. Here, we assessed the nature of the antagonism of different Escovopsis species against its host. We also evaluated the potential antagonism of Escovopsioides, a recently described fungal genus from the attine ant environment whose role in the colonies of these insects is unknown. We performed dual-culture assays to assess the interactions between L. gongylophorus and both fungi. We also evaluated the antifungal activity of compounds secreted by the latter on L. gongylophorus growth using crude extracts of Escovopsis spp. and Escovopsioides nivea obtained either in (1) absence or (2) presence of the mutualistic fungus. The physical interaction between these fungi and the mutualistic fungus was examined under scanning electron microscopy (SEM). Escovopsis spp. and E. nivea negatively affected the growth of L. gongylophorus, which was also significantly inhibited by both types of crude extract. These results indicate that Escovopsis spp. and E. nivea produce antifungal metabolites against the mutualistic fungus. SEM showed that Escovopsis spp. and E. nivea maintained physical contact with the mutualistic fungus, though no specialised structures related to mycoparasitism were observed. These results showed that Escovopsis is a destructive mycoparasite that needs physical contact for the death of the mutualistic fungus to occur. Also, our findings suggest that E. nivea is an antagonist of the ant fungal cultivar.
authors.affiliation: Departamento de Bioquímica e Microbiologia, Universidade Estadual Paulista (UNESP), Av. 24A, 1515, Bela Vista, Rio Claro, SP, 13506-900, Brazil.
authors.forename: Sadala Schmidt
authors.identifier: http://orcid.org/0000-0002-4164-9362
authors.initials: SS
authors.lastname: Varanda-Haifig
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, Rodovia Washington Luís, km 235, São Carlos, SP, 13565-905, Brazil.
authors.forename: Tatiane Regina
authors.initials: TR
authors.lastname: Albarici
authors.affiliation: Centro Interdisciplinar de Ciências da Vida, Universidade Federal da Integração Latino-Americana, Av. Tancredo Neves, 6731 - Bloco 6, Caixa Postal 2044, Foz do Iguaçu, PR, 85867-970, Brazil.
authors.forename: Pablo Henrique
authors.initials: PH
authors.lastname: Nunes
authors.affiliation: Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Campus Monte Carmelo. Rodovia LMG-746, km 1, Monte Carmelo, MG, 38500-000, Brazil.
authors.forename: Ives
authors.initials: I
authors.lastname: Haifig
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, Rodovia Washington Luís, km 235, São Carlos, SP, 13565-905, Brazil.
authors.forename: Paulo Cezar
authors.initials: PC
authors.lastname: Vieira
authors.affiliation: Departamento de Bioquímica e Microbiologia, Universidade Estadual Paulista (UNESP), Av. 24A, 1515, Bela Vista, Rio Claro, SP, 13506-900, Brazil. andrer@rc.unesp.br.
authors.forename: Andre
authors.identifier: http://orcid.org/0000-0002-4164-9362
authors.initials: A
authors.lastname: Rodrigues
mesh_terms: D000363:Agaricales / Q000378:metabolism*; D000818:Animals; D000898:Antibiosis / Q000502:physiology*; D000935:Antifungal Agents / Q000378:metabolism*; D001000:Ants / Q000382:microbiology*; D002457:Cell Extracts / Q000494:pharmacology*; D018920:Coculture Techniques; D006999:Hypocreales / Q000472:pathogenicity*; D008855:Microscopy, Electron, Scanning; D013559:Symbiosis / Q000502:physiology
chemical_list: D000935:Antifungal Agents; D002457:Cell Extracts
keywords: Antagonism; Hypocreales; Mycoparasitism; Tribe Attini