Caio Ambrosio Leal-Dutra

Leafcutter ants farm the domesticated fungal cultivar Leucoagaricus gongylophorus in subterranean nests containing up to hundreds of discrete garden chambers. The fungal cultivar produces edible symbiotic structures called gongylidia (nutritious swollen hyphal cells consumed by the ants) and expresses a form of polyploidy (multiple, genetically distinct nuclei per fungal cellular compartment). Yet, the fungus is also thought to lack the typical innate mechanisms for distributing these nuclei across its mycelial network of connected hyphal cells. Because new garden chambers are seeded by clonal fungal fragments from existing chambers, this raises questions about whether and how nuclear diversity is maintained across chambers within a colony. We hypothesized: (1) that mycelial fragmentation causes genetic and phenotypic instability in isolated fungal cultivar inoculates, but (2) that these variables remain stable when actively farmed by ants. We found that experimentally fragmented fungal isolates in Petri dishes lost gongylidium production and had higher growth rates. Microsatellite analyses confirmed that these phenotypic changes coincided with loss of alleles and fluorescence microscopy showed that gongylidium incompetency coincided with reduced nucleus numbers per cellular compartment. In contrast, natural fragmentation by ants in free‐ranging rainforest colonies coincided with minimal genetic divergence across garden chambers, even as divergence increased slightly with chamber distance. By integrating field and laboratory data, these results support: (1) that gongylidium production depends on genetic heterozygosity and multinuclearity, and (2) that ant farmers can maintain this genetic diversity. Resolving these stabilizing mechanisms will be crucial for understanding the genome evolution underlying a naturally selected crop domestication system.

Here, we report the discovery of four new agaricoid fungi in the Gliophorus irrigatus complex of the family Hygrophoraceae. Gliophorus alboviscidus sp. nov . from the UK is morphologically identical to the European G. irrigatus (which we neotypify), except that its basidiome is white or pale Buff-coloured vs. brownish-grey. Two new species from eastern North America, Gliophorus fumosus sp. nov . (provisional name Gliophorus sp. ‘irrigatus-IN01’) and Gliophorus parafumosus sp. nov . (previously labelled G. irrigatus ) resemble G. irrigatus s.s. in grey colour and morphology, but their distributions are restricted to North America. Phylogenetic reconstruction revealed that the two North American groups form distinct clades, with > 10% ITS sequence divergence from European G. irrigatus s.s. and from each other. Though G. alboviscidus sp. nov . is currently known only from two locations in the UK, searches for related sequences from eDNA (environmental DNA) sequence repositories (UNITE/GlobalFungi) suggested that this species is more widely distributed in Eurasia. G. fumosus and G. parafumosus sequences from eastern North America were divergent from both European G. irrigatus and G. alboviscidus ; both were more closely related to another species with a strong odour and white/Buff basidiomes from north-western North America, Hygrophorus subaromaticus , for which we sequenced the holotype and recombine in the genus Gliophorus . We also describe a new species from north-western North America, G. calunus sp. nov . (provisional name Gliophorus sp. ‘irrigatus-CA01’), based on vouchered specimens photographed and sequenced by a paraprofessional group, CA FUNDIS. We highlight the importance of citizen-scientist groups and paraprofessionals in documenting macrofungal species and their distributions via databases, such as iNaturalist, Mushroom Observer and MycoMap. Further, we discuss reasons that eDNA distributions are often larger than known distributions of basidiomes, including G. alboviscidus and G. fumosus .

In recent decades, there has been an increased interest in viruses of microorganisms (VoM) and international efforts to gather researchers interested in them. Here, we describe the 1st Brazilian Symposium on Viruses of Microorganisms (BrVoM), held on 1 August 2025 at the Federal University of Minas Gerais (UFMG, Belo Horizonte, Brazil) with institutional support from the Federal University of Alfenas (UNIFAL) and the Brazilian Society for Virology (SBV). The symposium greatly surpassed expectations, gathering nearly 300 attendees from all Brazilian geographical regions. The scientific program included keynote and thematic lectures covering bacteriophages, fungal viruses, giant viruses, and microbial resources regulation. The event was remarkable for its collaborative spirit and inclusion of early career attendees. The success of this first edition highlights the vitality of the Brazilian community working on microbial viruses and sets the stage for future editions.

Here we report the discovery of four new agaricoid fungi in the Gliophorus irrigatus complex of the family Hygrophoraceae. Gliophorus alboviscidus sp. nov. from the UK is morphologically identical to the European G. irrigatus (which we neotypify), except that its basidiome is white or pale Buff coloured vs brownish grey. Two new species from eastern North America, Gliophorus fumosus sp. nov. (provisional name Gliophorus sp. ‘irrigatus-IN01’), and Gliophorus parafumosus sp. nov (previously labelled G. irrigatus ) resemble G. irrigatus s.s. in colour and morphology but their distributions are restricted to North America. Phylogenetic reconstruction revealed that these samples form distinct clades, with >10% ITS sequence divergence from European G. irrigatus s.s. and from each other. Though G. alboviscidus sp. nov. is currently known only from two locations in the UK, searches for related sequences from eDNA (environmental DNA) sequence repositories (UNITE/GlobalFungi) suggested that this species is more widely distributed in Eurasia. G. fumosus and G. parafumosus sequences from eastern North America were divergent from both European G. irrigatus and G. alboviscidus ; both were more closely related to another species with a strong odour and white/Buff basidiomes from northwestern North America, Hygrophorus subaromaticus for which we sequenced the holotype and recombine in the genus Gliophorus . We also describe a new species from northwestern North America, G. calunus sp. nov. (provisional name Gliophorus sp. ‘irrigatus-CA01’), based on vouchered specimens photographed and sequenced by an paraprofessional group, CA FUNDIS. We highlight the importance of citizen scientist groups and paraprofessionals in documenting macrofungal species and their distributions via databases such as iNaturalist, Mushroom Observer and MycoMap. Further, we discuss reasons eDNA distributions are often larger than known distributions of basidiomes, including G. alboviscidus and G. fumosus .

Fungus-farming ants cultivate multiple lineages of fungi for food, but, because fungal cultivar relationships are largely unresolved, the history of fungus-ant coevolution remains poorly known. We designed probes targeting >2000 gene regions to generate a dated evolutionary tree for 475 fungi and combined it with a similarly generated tree for 276 ants. We found that fungus-ant agriculture originated ~66 million years ago when the end-of-Cretaceous asteroid impact temporarily interrupted photosynthesis, causing global mass extinctions but favoring the proliferation of fungi. Subsequently, ~27 million years ago, one ancestral fungal cultivar population became domesticated, i.e., obligately mutualistic, when seasonally dry habitats expanded in South America, likely isolating the cultivar population from its free-living, wet forest–dwelling conspecifics. By revealing these and other major transitions in fungus-ant coevolution, our results clarify the historical processes that shaped a model system for nonhuman agriculture.

The naturally selected fungal crop (Leucoagaricus gongylophorus) farmed by leafcutter ants shows striking parallels with artificially selected plant crops domesticated by humans (e.g. polyploidy, engorged nutritional rewards, and dependence on cultivation). To date, poorly resolved L. gongylophorus genome assemblies based on short-read sequencing have constrained hypotheses about how millions of years under cultivation by ants shaped the fungal crop genome and potentially drove domestication. We use PacBio HiFi sequencing of L. gongylophorus from the leafcutter ant Atta colombica to identify 18 putatively novel biosynthetic gene clusters that likely cemented life as a cultivar (e.g. plant fragment degradation, ant–farmer communication, and antimicrobial defense). Comparative analyses with cultivated and free-living fungi showed genomic signatures of stepwise domestication transitions: (i) free-living to ant-cultivated: loss of genes conferring stress response and detoxification; (ii) hyphal food to engorged nutritional rewards: expansions of genes governing cellular homeostasis, carbohydrate metabolism, and siderophore biosynthesis; and (iii) detrital provisioning to freshly cut plant fragments: gene expansions promoting cell wall biosynthesis, fatty acid metabolism, and DNA repair. Comparisons across L. gongylophorus fungi farmed by 3 leafcutter ant species highlight genomic signatures of exclusively vertical clonal propagation and widespread transposable element activity. These results show how natural selection can shape domesticated cultivar genomes toward long-term ecological resilience of farming systems that have thrived across millennia.

Leafcutter ants are dominant herbivores in the Neotropics and rely on a fungus (Leucoagaricus gongylophorus) to transform freshly gathered leaves into a source of nourishment rather than consuming the vegetation directly. Here we report two virus-like particles that were isolated from L. gongylophorus and observed using transmission electron microscopy. RNA sequencing identified two +ssRNA mycovirus strains, Leucoagaricus gongylophorus tymo-like virus 1 (LgTlV1) and Leucoagaricus gongylophorus magoulivirus 1 (LgMV1). Genome annotation of LgTlV1 (7401 nt) showed conserved domains for methyltransferase, endopeptidase, viral RNA helicase, and RNA-dependent RNA polymerase (RdRp). The smaller genome of LgMV1 (2636 nt) contains one open reading frame encoding an RdRp. While we hypothesize these mycoviruses function as symbionts in leafcutter farming systems, further study will be needed to test whether they are mutualists, commensals, or parasites.

The naturally selected fungal crop ( Leucoagaricus gongylophorus ) farmed by leafcutter ants shows striking parallels with artificially selected plant crops domesticated by humans (e.g., polyploidy, engorged nutritional rewards, dependence on cultivation). To date, poorly resolved L. gongylophorus genomes based on short-read sequencing have constrained hypotheses about how millions of years under cultivation by ants shaped the fungal crop genome and potentially drove domestication. We use PacBio HiFi sequencing of L. gongylophorus from the leafcutter ant Atta colombica to identify 18 putatively novel biosynthetic gene clusters that likely cemented life as a cultivar (e.g., plant fragment degradation, ant-farmer communication, antimicrobial defense). Comparative analyses with cultivated and free-living fungi showed genomic signatures of stepwise domestication transitions: 1) free-living to ant-cultivated: loss of genes conferring stress response and detoxification, 2) hyphal food to engorged nutritional rewards: expansions of genes governing cellular homeostasis, carbohydrate metabolism, and siderophore biosynthesis, and 3) detrital provisioning to freshly cut plant fragments: gene expansions promoting cell wall biosynthesis, fatty acid metabolism, and DNA repair. Comparisons across L. gongylophorus fungi farmed by three leafcutter ant species highlight genomic signatures of exclusively vertical clonal propagation and widespread transposable element activity. These results show how natural selection can shape domesticated cultivar genomes towards long-term ecological resilience of farming systems that have thrived across millennia.