Horizontal and Vertical Transmission of a Mycovirus Closely Related to the Partitivirus RhsV717 That Confers Hypovirulence in Rhizoctonia solani

Abstract

Rhizoctonia solani virus717 (RhsV717) was isolated from the Rhizoctonia solani (R. solani) AG-2 strain Rhs717. This study isolated a virus designated as Rhizoctonia solani partitivirus BS-5 (RsPV-BS5) from the R. solani AG-3 strain BS-5, the causal agent of tobacco target spot disease. The virus was identified as a strain of RhsV717. Transmission electron microscopy (TEM) images showed that RsPV-BS5 had virus particles with a diameter of approximately 40 nm. Importantly, it can be horizontally transmitted through hyphal anastomosis and vertically transmitted via sexual basidiospores. Furthermore, this study demonstrated that RsPV-BS5 infection significantly impedes mycelial growth and induces hypovirulence in tobacco leaves. Thus, RsPV-BS5 presents a promising avenue for biocontrolling tobacco target spot disease. Transcriptome analysis unveiled differential expression of four genes related to cell wall-degrading enzymes between two isogenic strains, 06-2-15V and 06-2-15. These findings shed light on the molecular mechanism through which RsPV-BS5 reduces host pathogenicity.

Transmission of Oyster Mushroom Spherical Virus to Progeny via Basidiospores and Horizontally to a New Host Pleurotus floridanus

“…For instance, CHV1 can be transmitted to conidiospore offspring with a 100% transmission rate but maintains only 50% virulence in sexual spores offspring [11]. Similarly, RsPV-BS5 was found in R. solani basidiospores, confirming its vertical transmission [13]. In L. edodes, the prevalence rate of LeSV in basidiospores was 90% [16].…”

“…Similarly, the dsRNA Fusarium graminearum hypovirus 1 (FgHV1) infecting F. graminearum can be transmitted vertically through asexual spores with a 100% transmission rate [ 12 ]. Another dsRNA Rhizoctonia solani partitivirus (RsPV-BS5) can exist stably in the sexual spores of R. solani AG-3, indicating that RsPV-BS5 can carry out vertical transmission in R. solani [ 13 ]. However, few studies exist about the vertical transmission of mycoviruses within edible mushroom species.…”

Fusarium sacchari hypovirus 1, a Member of Hypoviridae with Virulence Attenuation Capacity in Phytopathogenic Fusarium Species

“…The strains were collected from various locations in Fujian and Guangxi, indicating a relatively wide spread of FsHV1. Mycoviruses can readily be transmitted vertically via fungal spores, but horizontal transmission via hyphal fusion may be limited by vegetative incompatibility among different incompatibility of the same species or different species [ 35 ]. Thus, vegetative incompatibility is a major factor hindering the spread of fungal viruses [ 36 ].…”

Comparative Analysis of Viromes Identified in Multiple Macrofungi

“…The multiple-sequence alignment of RNA-dependent RNA polymerase proteins (RdRps), methyltransferase, and conserved helicase domains was performed by using Clustal Omega ( ) (accessed on 25 December 2023). Total RNA was used as a template to synthesize first-strand cDNA and a 25 µL PCR reaction mixture was prepared, containing components like 12.5 µL ExTaq Mix (TaKaRa, Wuhan, China), 1 µL cDNA template, 2 µL specific primers ( Supplementary Materials Table S3 ), and 9.5 µL ddH 2 O, as described previously [ 28 , 31 ]. PCR products were visualized in 1.5% agarose gels (Biowest, Hong Kong, China) with GelRed (Saibeike, Beijing, China).…”

“…The purified PCR amplicons were inserted into the pMD18-T vector and then transformed into Escherichia coli DH5α competent cells. Three positive clones were selected from the transformed competent cells for sequencing analysis (Tianyi Huayu Gene Technology, Wuhan, China) [ 31 ].…”