Fungal genotype determines survival of Drosophila melanogaster when competing with Aspergillus nidulans

Abstract

Fungi produce an astonishing variety of secondary metabolites, some of which belong to the most toxic compounds in the living world. Several fungal metabolites have anti-insecticidal properties which may yield advantages to the fungus in competition with insects for exploitation of environmental resources. Using the Drosophila melanogaster/Aspergillus nidulans ecological model system to assess secondary metabolite mutant genotypes, we find a major role for the veA allele in insect/fungal confrontations that exceeds the influence of other factors such as LaeA. VeA along with LaeA is a member of a transcriptional complex governing secondary metabolism in A. nidulans. However, historically a mutant veA allele, veA1 reduced in secondary metabolite output, has been used in many studies of this model organism. To test the significance of this allele in our system, Aspergillus nidulans veA wild type, veA1, ΔveA and ΔlaeA were evaluated in confrontation assays to analyze egg laying activity, and the survival rate of larvae. The veA1 genetic background led to a significant increase of larval survival. Adult flies were observed almost exclusively on veA1, ΔveA or ΔlaeA genetic backgrounds, suggesting a role for the velvet complex in insect/fungal interactions. This effect was most profound using the veA1 mutant. Hence, larval survival in confrontations is highly affected by the fungal genotype.

The Aspergilli and Their Mycotoxins: Metabolic Interactions With Plants and the Soil Biota

“…Non-aflatoxigenic knockout and low toxin-producing strains of Aspergillus are less capable of antagonizing insect populations (Regulin and Kempken, 2018). In addition to balancing selection on mycotoxin production, it must be noted that insect adaptation to mold competition seems to favor tolerance instead of resistance (Trienens and Rohlfs, 2011).…”

Caenorhabditis elegans as an Infection Model for Pathogenic Mold and Dimorphic Fungi: Applications and Challenges

“…Several model organisms have been adopted for studying of dimorphic and filamentous pathogenic fungi, including invertebrate models such as Drosophila melanogaster (Lamaris et al, 2008;Regulin and Kempken, 2018;Sampaio et al, 2018;Wurster et al, 2019), Galleria mellonella (Gomez-Lopez et al, 2014;Long et al, 2018;Silva et al, 2018;Staniszewska et al, 2020), Bombyx mori (Matsumoto et al, 2013;Uchida et al, 2016;Nakamura et al, 2017;Matsumoto and Sekimizu, 2019), Caenorhabditis elegans (Okoli and Bignell, 2015;Song et al, 2019;Wong et al, 2019;Ahamefule et al, 2020a), and vertebrate models such as mice (Fakhim et al, 2018;Skalski et al, 2018;Wang et al, 2018;Mueller et al, 2019), guinea pigs (Vallor et al, 2008;Nadaşet al, 2013;Garvey et al, 2015), and zebrafish (Chen et al, 2015;Knox et al, 2017;Koch et al, 2019;Kulatunga et al, 2019).…”

Fungal Secondary Metabolites: Fusarium spp. and Microdochium spp.

“…Why was the synthesis of the pigment not stimulated by grazing? The likely reason was that as in most studies of interactions between A. nidulans and arthropods conducted thus far, in this study, an A. nidulans strain carrying mutation veA1 was used, which is defective in secondary metabolite production and defence responses 38 . VeA is part of the velvet complex, which is needed for aurofusarin synthesis in F. graminearum 39 .…”