The complete genomic sequence of a novel mycovirus from Rhizoctonia solani AG-1 IA strain B275

Abstract

The complete genome of a novel mycovirus, Rhizoctonia solani dsRNA virus 1 (RsRV1) was sequenced and analyzed. It is composed of two dsRNA genome segments, 2379 bp and 1811 bp in length, which were referred to as RsRV1-1 and RsRV1-2, respectively. RsRV1-1 contains a single open reading frame (ORF1), which has a conserved RNA-dependent RNA polymerase (RdRp) domain, whereas RsRV1-2 contains a single ORF2, which might encode a multifunctional protein. The genome organization of RsRV1 is similar to that of members of the family Partitiviridae. However, phylogenetic analysis indicated that RsRV1 formed a distinct clade together with three other unclassified viruses, suggesting that RsRV1 may belong to a new family of dsRNA mycoviruses. This is the first report of the full-length nucleotide sequence of a novel dsRNA mycovirus, RsRV1, infecting R. solani AG-1 IA strain B275, the causal agent of rice sheath blight.

Description and prevalence of a putative novel mycovirus within the conifer pathogen Gremmeniella abietina

“…3). This new virus group has been hypothesised to be (closely) related to members of the family Partitiviridae [44,49,50]. Most of these viruses have bipartite genomes with sizes similar to those of partitiviruses (1,700 to 2,400 bp).…”

“…abietina RNA virus 6 (GaRV6) seems to be part of an unclassified mycovirus group that is likely to be proposed as a novel virus family in the future [28]. Its members are hosted by important plant pathogens, such as H. annosum [44], C. parasitica (GenBank accession numbers KC549809 and KC549810), Rhizoctonia solani [50], Fusarium graminearum [49], and the endophyte Curvularia protuberata [25]. Two other mycoviruses, infecting Ustilaginoidea virens [20] and Alternaria longipes [48], which might belong to the same virus species, group somewhat outside the remaining virus species but still within the same cluster (Fig.…”

“…So far, the true role of the members of this novel taxon within their fungal hosts remains unclear. Rhizoctonia solani dsRNA virus 1 (RsRV1) was isolated from a strain that showed a slower growth rate and reduced pathogenicity when compared with virulent strains [50]. HetRV6 confers beneficial, cryptic or detrimental effects to Heterobasidion growth in different situations [19].…”

Susceptibility of Wheat Varieties to Soil-Borne <i>Rhizoctonia</i> Infection

“…For example, a basic oligopeptide of Bacillus subtilis exhibited excellent and broad spectrum antimicrobial activity in our experiments [93] and would fit for control of all four important soil borne pathogens of wheat. The incorporation of Rhizoctonia specific mycovirus into genome of cereals also is a promising possibility [94], with special regard to root border cells. These, detached living cells form the "front line" in the soil, the special part of rhizosphere, described as a system first by Hawes [95], where the plant controls the microenvironment with these specially progammed cells [96].…”

Full genome sequence of a putative novel mitovirus isolated from Rhizoctonia cerealis

“…The viruses Rhizoctonia virus M2 (RVM2), Rhizoctonia solani partitivirus 2 (RsPV2), and Rhizoctonia solani dsRNA virus 1 (RsRV1) have been reported in another member of the genus Rhizoctonia, Rhizoctonia solani AG-1 IA [9,20,21]. The only reported mycovirus in R. cerealis is Rhizoctonia cerealis endornavirus 1 (RcEV1) [10].…”