Macrophomina phaseolina is an important necrotrophic phytopathogenic fungus and cause extensive damage in many oilseed crops. Twelve M.phaseolina isolates with diverse biological phenotypes were selected for a high-throughput sequencing-based metatranscriptomic and bioinformatics analysis to identify viruses infecting M.phaseolina . The analysis identified 40 partial or nearly complete viral genome segments, 31 of which were novel viruses. Among these viral sequences, 43% of the viral genomes were double-stranded RNA (dsRNA), 47% were positive single-stranded RNA (ssRNA+), and the remaining 10% were negative sense-stranded RNA (ssRNA−). The 40 viruses showed affinity to 13 distinct viral lineages, including Bunyavirales (four viruses), Totiviridae (three viruses), Chrysoviridae (five viruses), Partitiviridae (four viruses), Hypoviridae (one virus), Endornaviridae (two viruses), Tombusviridae (three viruses), Narnaviridae (one virus), Potyviridae (one virus), Bromoviridae (one virus), Virgaviridae (six viruses), ‘Fusagraviridae’ (five viruses), and Ourmiavirus (four viruses). Two viruses are closely related to two families, Potyviridae and Bromoviridae , which previously contained no mycovirus species. Moreover, nine novel viruses associated with M.phaseolina were identified in the family Totiviridae , Endornaviridae , and Partitiviridae . Coinfection with multiple viruses is prevalent in M.phaseolina , with each isolate harboring different numbers of viruses, ranging from three to eighteen. Furthermore, the effects of the viruses on the fungal host were analyzed according to the biological characteristics of each isolate. The results suggested that M.phaseolina hypovirus 2, M.phaseolina fusagravirus virus 1-5 (MpFV1-5), M.phaseolina endornavirus 1-2 (MpEV1-2), M.phaseolina ourmia-like virus 1-3 (MpOLV1-3), M.phaseolina mitovirus 4 (MpMV4), and M.phaseolina mycobunyavirus 1-4 (MpMBV1-4) were only detected in hypovirulent isolates. Those viruses associated with hypovirulence might be used as biological control agents as an environmentally friendly alternative to chemical fungicides. These findings considerably expand our understanding of mycoviruses in M.phaseolina and unvailed the presence of a huge difference among viruses in isolates from different hosts in distant geographical regions. Together, the present study provides new knowledge about...

Fusarium oxysporum is a cosmopolitan plant pathogen causing Fusarium wilt and Fusarium root rot in many economically important crops. There is still limited information about mycoviruses that infect F. oxysporum. Here, a novel mitovirus tentatively named Fusarium oxysporum mitovirus 1 (FoMV1) was identified from F. oxysporum strain B2-10. The genome of FoMV1 is 2,453 nt in length with a predicted AU content of 71.6%, and contains one large open reading frame (ORF) using the fungal mitochondrial genetic code. The ORF encodes RNA-dependent RNA polymerases (RdRp) of 723 amino acids with a molecular mass of 84.98 kDa. The RdRp domain of FoMV1 shares 29.01–68.43% sequence similarity to the members of the family Mitoviridae. Phylogenetic analysis further suggested that FoMV1 is a new member of a distinct species in the genus Mitovirus.