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

Abstract

A novel mycovirus named Fusarium oxysporum f. sp. dianthi mitovirus 1 (FodMV1) has been identified infecting a strain of Fusarium oxysporum f. sp. dianthi from Colombia. The genome of FodMV1 is 2313 nt long, and comprises a 172-nt 5’-UTR, a 2025-nt single ORF encoding an RdRp of 675 amino acid residues, and a 113-nt 3´-UTR. Homology BlastX searches identifies FodMV1 as a novel member of the genus Mitovirus in the family Narnaviridae. As the rest of mitoviruses, the genome of FodMV1 presents a high percentage of A+U (58.8%) and contains a number of UGA codons that encode the amino acid tryptophan rather than acting as stop codons as in the universal genetic code. Another common feature with other mitoviruses is that the 5′- and 3′-UTR regions of FodMV1 can be folded into potentially stable stem-loop structures. Result from phylogenetic analysis place FodMV1 in a different clade than the rest of mitoviruses described in other Fusarium spp. Incidence of FodMV1-infections in the collection of F. oxysporum f. sp. dianthi isolates analyzed is relatively high. Of particular interest is the fact that FodMV1 has been detected infecting isolates from two geographical areas as distant as Spain and Colombia.

Molecular Characterization of the First Alternavirus Identified in Fusarium oxysporum

“…Numerous mycoviruses have been described from different families, infecting many phytopathogenic fungi and entomopathogenic fungi [ 2 , 8 , 46 ]. However, among the hundreds of mycoviruses described so far, only six mycoviruses have been identified in F. oxysporum , an important phytopathogenic species [ 34 , 35 , 36 , 37 , 38 , 39 ], with no reports of any viruses belonging to the proposed family “Alternaviridae”. FoAV1 is the first alternavirus described to infect F. oxysporum .…”

“…dianthi mitovirus 1 (FodMV1), classified as family Narnaviridae ; Fusarium oxysporum f. sp. dianthi hypovirus 2 (FodHV2), classified as family Hypoviridae ; Hadaka Virus 1 (HadV1), classified as family Polymycoviridae ; and Fusarium oxysporum ourmia-like virus 1 (FoOuLV1), classified as family Botourmiaviridae [ 34 , 35 , 36 , 37 , 38 , 39 ]. Only FodV1 and FoOuLV1 are known to cause hypovirulence [ 39 , 40 ].…”

A Novel Ourmia-Like Mycovirus Confers Hypovirulence-Associated Traits on Fusarium oxysporum

“…Fusarium wilt caused by F. oxysporum affects a large number of economically important crops. The pathogenic species contain a diversity of host-plant–specific forms ( Torres-Trenas and Pérez-Artés, 2020 ), with different formae speciales potentially existing together in the soil concurrently. The hypovirulent traits of FoOuLV1 reported here can be transmitted horizontally from FoM strains to virus-free FoM strains and to FoC strains.…”

“…Many mycoviruses have been identified from the genus Fusarium ( Cho et al, 2013 ); but, to our knowledge, only three mycoviruses have been identified in F. oxysporum (FoCV1, FodV1, and FodMV1). Furthermore, among these, only FodV1 induces hypovirulence ( Sharzei et al, 2007 ; Lemus-Minor et al, 2015 ; Torres-Trenas and Pérez-Artés, 2020 ). In this study, FoOuLV1 was not only able to induce hypovirulence in F. oxysporum but also exhibited significant biological control effects against bitter gourd Fusarium wilt in the pot and field experiments.…”

“…dianthi mitovirus 1 (FodMV1) has been identified from F. oxysporum f. sp. dianthi , but it has no hypovirulence trait ( Torres-Trenas and Pérez-Artés, 2020 ).…”