Isolation and characterization of a novel mycovirus from Penicillium digitatum

Abstract

A novel double-stranded RNA virus designated Penicillium digitatum virus 1 (PdV1) was isolated from the citrus fruit rot pathogen P. digitatum (HS-RH1). The full-length cDNA sequence of the dsRNA/PdV1 (5211bp) possesses two partially overlapping open reading frames, which encode a coat protein (CP) and a putative RNA-dependent RNA polymerase (RdRp), respectively. Phylogenetic analysis based on multiple alignments of the amino acid sequences of the RdRp and CP indicated that PdV1 tentatively belongs to the genus Victorivirus in the Totiviridae family. Electron micrographs of negatively stained viral particles purified from the peak fraction of sucrose density gradient centrifugation showed spherical particles ~35nm in diameter. Transfection experiments with purified virions indicated that PdV1 could reduce the vegetative growth and virulence of P. digitatum strain HS-F6. In summary, we report the first isolation and characterization of a mycovirus from P. digitatum that contributes to the hypovirulence phenotypes of the host strain.

Characterization of two novel mycoviruses from Penicillium digitatum and the related fungicide resistance analysis

“…These virus-like particles in ~33 nm diameter were further verified to be virions of the Victorivirus with dsRNA1 genome (i.e. the virus particles of previously reported PdV1) 17 (Fig. S2C,D ).…”

“…The infection rates of 39.3% (35/89) suggested a well prevalence of dsRNA mycovirus infection in P. digitatum strains. According to partial sequencing analysis, 24 P. digitatum isolates are infected with mycoviruses, belonging to Totiviridae family and sharing great similarity with PdV1 17 , and 9 P. digitatum isolates are infected with mycoviruses, belonging to Partitivirdae family and sharing great similarity with PsV-S 24 . Here, mycoviruses coinfection was observed in two P. digitatum strains.…”

“…One strain harbors two mycoviruses belonging to Totiviridae and Partitivirdae families which members have been well documented in many fungal strains 17 , 25 . The other strain (HB-36) harbors three mycoviruses, the one (PdV1) previously reported as Totividae member 17 and the other two characterized as polymycovirus and Narna-like virus. Here, the member of Narna-like viruses and the member of polymycovirus were at first time molecularly identified in Penicillium strains.…”

“…Up to date, the extensive evidence on dsRNA and/or ssRNA mycoviruses has been addressed in fungal phytopathogens including Cryphonectria parasitica , Sclerotinia sclerotiorum , Rosellinia necatrix , Botrytis species, and Fusarium species 16 . In contrast, apart from Penicillium digitatum virus 1 (PdV1) 17 , no other mycovirus has been reported from citrus pathogenic fungi ( Penicillium species).…”

Discovery of new mycoviral genomes within publicly available fungal transcriptomic datasets

“…For five of the six other Victoriviruses identified in this study, a 60% pairwise identity would not distinguish between viral sequences, only the host-based criteria. The sixth virus, PdTV1-KH8, shares 97% (RdRP) and 98% (CP) identity with the already published sequence for Penicillium digitatum virus 1 (PdV1) [29] thus neither the sequence-based nor host-based criteria are met. Notably, PdTV2 and PdTV1-KH8 were both identified from the same data sample, however they share only 33.5% identity.…”