Mycoviruses in Fusarium Species: An Update

Abstract

Fusarium is an important genus of plant pathogenic fungi, and is widely distributed in soil and associated with plants worldwide. The diversity of mycoviruses in Fusarium is increasing continuously due to the development and extensive use of state-of-the-art RNA deep sequencing techniques. To date, fully-sequenced mycoviruses have been reported in 13 Fusarium species: Fusarium asiaticum, F. boothii, F. circinatum, F. coeruleum, F. globosum, F. graminearum, F. incarnatum, F. langsethiae, F. oxysporum, F. poae, F. pseudograminearum, F. solani , and F. virguliforme . Most Fusarium mycoviruses establish latent infections, but some mycoviruses such as Fusarium graminearum virus 1 (FgV1), Fusarium graminearum virus-ch9 (FgV-ch9), Fusarium graminearum hypovirus 2 (FgHV2), and Fusarium oxysporum f. sp. dianthi mycovirus 1 (FodV1) cause hypovirulence. Rapid advances in various omics technologies used to elucidate genes or biological processes can facilitate an improved understanding of mycovirus-host interactions. The review aims to illuminate the recent advances in studies of mycoviruses in Fusarium , including those related to diversity, molecular mechanisms of virus-host interaction. We also discuss the induction and suppression of RNA silencing including the role of RNAi components as an antiviral defense response.

A Survey of Mycoviral Infection in Fusarium spp. Isolated from Maize and Sorghum in Argentina Identifies the First Mycovirus from Fusarium verticillioides

“…The advent and application of next generation sequencing techniques (e.g., RNA-seq and Metagenomic) have greatly increased the pace of mycovirus discovery in a wide diversity of fungi [ 5 , 6 ]. Up to date, mycoviruses had been identified in 16 different Fusarium species [ 52 , 58 , 77 , 85 ] including F. andiyazi , F. asiaticum , F. boothii , F. circinatum , F. coeruleum , F. globosum , F. graminearum , F. incarnatum , F. langsethiae , F. oxysporum , F. poae , F. pseudograminearum , F. sacchari , F. solani , F. culmorum and F. virguliforme . However, no mycovirus had been reported so far in F. verticillioides , the major causal agent of corn ear rot and fumonisin producer in the grains.…”

“…Mitoviruses are widely distributed in nature [ 76 , 99 , 100 ], including a great diversity of fungal species [ 96 ]. Mitoviruses are the most common mycoviruses isolated from Fusarium species [ 52 , 77 , 96 ]. Infections caused by the majority of the mitoviruses reported so far are asymptomatic.…”

“…The search for mycoviruses that attenuate fungal virulence, and have therefore potential as biological control agents [ 16 ], generally focuses on the identification and characterization of those naturally infecting the pathogen to be controlled [ 18 , 19 ]. To date, mycoviruses have been isolated from a variety of Fusarium species [ 51 , 52 ]. These mycoviruses belong to a wide range of viral families with dsRNA, +ssRNA, and −ssRNA genomes (recently reviewed by Li et al [ 52 ]).…”

“…To date, mycoviruses have been isolated from a variety of Fusarium species [ 51 , 52 ]. These mycoviruses belong to a wide range of viral families with dsRNA, +ssRNA, and −ssRNA genomes (recently reviewed by Li et al [ 52 ]). However, only a limited number of them have been associated with the induction of phenotypic alterations in the host fungus.…”

The ORF2 protein of Fusarium graminearum virus 1 suppresses the transcription ofFgDICER2andFgAGO1to limit host antiviral defences

“…In addition to reducing yield, this fungal pathogen contaminates cereal grain with mycotoxins, such as trichothecene and zearalenone, that are harmful to animals and humans (Ferrigo et al , ). Several mycoviruses of F. graminearum have recently been isolated and characterized (Li et al , ). Our laboratory previously characterized four different mycoviruses of F. graminearum : Fusarium graminearum virus 1 (FgV1), FgV2, FgV3 and FgV4, phylogenetically related to members of the Fusariviridae , Chrysoviridae , Totiviridae and Partitiviridae , respectively (Cho et al ., , Lee et al , ).…”