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It has been 49 years since the last discovery of a new virus family in the model yeastSaccharomyces cerevisiae. A large-scale screen to determine the diversity of double-stranded RNA (dsRNA) viruses inS.cerevisiaehas identified multiple novel viruses from the familyPartitiviridaethat have been previously shown to infect plants, fungi, protozoans, and insects. MostS.cerevisiaepartitiviruses (ScPVs) are associated with strains of yeasts isolated from coffee and cacao beans. The presence of partitiviruses was confirmed by sequencing the viral dsRNAs and purifying and visualizing isometric, non-enveloped viral particles. ScPVs have a typical bipartite genome encoding an RNA-dependent RNA polymerase (RdRP) and a coat protein (CP). Phylogenetic analysis of ScPVs identified three species of ScPV, which are most closely related to viruses of the genusCryspovirusfrom the mammalian pathogenic protozoanCryptosporidium parvum. Molecular modeling of the ScPV RdRP revealed a conserved tertiary structure and catalytic site organization when compared to the RdRPs of thePicornaviridae. The ScPV CP is the smallest so far identified in thePartitiviridaeand has structural homology with the CP of other partitiviruses but likely lacks a protrusion domain that is a conspicuous feature of other partitivirus particles. ScPVs were stably maintained during laboratory growth and were successfully transferred to haploid progeny after sporulation, which provides future opportunities to study partitivirus-host interactions using the powerful genetic tools available for the model organismS.cerevisiae. 

Abstract Escovopsisis a diverse group of fungi, which are considered specialized parasites of the fungal cultivars of fungus-growing ants. The lack of a suitable taxonomic framework and phylogenetic inconsistencies have long hamperedEscovopsisresearch. The aim of this study is to reassess the genusEscovopsisusing a taxonomic approach and a comprehensive multilocus phylogenetic analysis, in order to set the basis of the genus systematics and the stage for futureEscovopsisresearch. Our results support the separation ofEscovopsisinto three distinct genera. In light of this, we redefineEscovopsisas a monophyletic clade whose main feature is to form terminal vesicles on conidiophores. Consequently,E. kreiseliiandE. trichodermoideswere recombined into two new genera,SympodioroseaandLuteomyces, asS.kreiseliiandL.trichodermoides, respectively. This study expands our understanding of the systematics ofEscovopsisand related genera, thereby facilitating future research on the evolutionary history, taxonomic diversity, and ecological roles of these inhabitants of the attine ant colonies.