Mitovirus and Mitochondrial Coding Sequences from Basal Fungus Entomophthora muscae

Abstract

Fungi constituting the Entomophthora muscae species complex (members of subphylum Entomophthoromycotina, phylum Zoopagamycota) commonly kill their insect hosts and manipulate host behaviors in the process. In this study, we made use of public transcriptome data to identify and characterize eight new species of mitoviruses associated with several different E. muscae isolates. Mitoviruses are simple RNA viruses that replicate in host mitochondria and are frequently found in more phylogenetically apical fungi (members of subphylum Glomeromyoctina, phylum Mucoromycota, phylum Basidiomycota and phylum Ascomycota) as well as in plants. E. muscae is the first fungus from phylum Zoopagomycota, and thereby the most phylogenetically basal fungus, found to harbor mitoviruses to date. Multiple UGA (Trp) codons are found not only in each of the new mitovirus sequences from E. muscae but also in mitochondrial core-gene coding sequences newly assembled from E. muscae transcriptome data, suggesting that UGA (Trp) is not a rarely used codon in the mitochondria of this fungus. The presence of mitoviruses in these basal fungi has possible implications for the evolution of these viruses.

Survey of Early-Diverging Lineages of Fungi Reveals Abundant and Diverse Mycoviruses

“…Interestingly, the new viruses in this group are mostly hosted by fungi in the Mucoromycota or Zoopagomycota. Previous evidence suggests the origin of mitoviruses was a common ancestor of Mucoromyota and Zoopagomycota, which was followed by cospeciation of host and mitoviruses and horizontal transmission to plants (13,24). Our findings support this hypothesis, but sequence data are still limited for viruses in Chytridiomycota, Blastocladiomycota, and Neocallimastigomycota.…”

Characterization and Incidence of the First Member of the Genus Mitovirus Identified in the Phytopathogenic Species Fusarium oxysporum

“…Due to their possible use as biological control agents [3][4][5][6][7]16,17], and to the current low cost of mass sequencing techniques [18,29], the description of new mycoviruses, in general, and of new mitoviruses in particular, is increasing considerably in recent times. Mitoviruses have been found in many phytopathogenic fungi, including both ascomycetes and basidiomycetes [23][24][25][31][32][33][34][35][36][37], and also in many entomopathogenic fungi [8,13,14]. Nevertheless, among the hundreds of mitoviruses described so far, none has been identified infecting a strain of the important phytopathogenic species F. oxysporum.…”

“…Mycoviruses have been reported infecting all major taxonomic groups of fungi, including phytopathogenic and entomopathogenic fungi [3][4][5][6][7][8][9][10][11][12][13][14]. Although most of the mycoviruses described are cryptic, some species identified from different viral families show variable effects on the phenotype of their host isolate, including the induction of hypovirulence.…”

“…Mitoviruses have been identified in plants and in phytopathogenic and entomopathogenic fungi [8,13,14,[21][22][23][24][25]. Mitoviruses have a genome formed by a single ssRNA molecule with a length from 2.3 to 2.9 kb, although they are normally identified in their replicative form as dsRNA.…”

Viruses of endophytic and pathogenic forest fungi

“…Advanced mycovirus studies are now focused on providing data on the host transcriptome and RNA signaling [31,68,80]. HTS has been successfully used to detect known and unknown viruses from fungal samples [81] as well as detect mycovirus genome segments through small RNA deep sequencing [25,82].…”