RNA-seq Analysis of Rhizoctonia solani AG-4HGI Strain BJ-1H Infected by a New Viral Strain of Rhizoctonia solani Partitivirus 2 Reveals a Potential Mechanism for Hypovirulence

Abstract

Rhizoctonia solani partitivirus 2 (RsPV2), in the genus Alphapartitivirus, confers hypovirulence on Rhizoctonia solani AG-1-IA, the causal agent of rice sheath blight. In this study, a new strain of RsPV2 obtained from R. solani AG-4HGI strain BJ-1H, the causal agent of black scurf on potato, was identified and designated as Rhizoctonia solani partitivirus 2 strain BJ-1H (RsPV2-BJ). An RNA sequencing analysis of strain BJ-1H and the virus RsPV2-BJ-free strain BJ-1H-VF derived from strain BJ-1H was conducted to investigate the potential molecular mechanism of hypovirulence induced by RsPV2-BJ. In total, 14319 unigenes were obtained, and 1341 unigenes were identified as differentially expressed genes (DEGs), with 570 DEGs being down-regulated and 771 being up-regulated. Notably, several up-regulated DEGs were annotated to cell-wall-degrading enzymes, including β-1,3-glucanases. Strain BJ-1H exhibited increased expression of β-1,3-glucanase following RsPV2-BJ infection, suggesting that cell wall autolysis activity in R. solani AG-4HGI strain BJ-1H might be promoted by RsPV2-BJ, inducing hypovirulence in its host fungus R. solani AG-4HGI. To the best of our knowledge, this is the first report on the potential mechanism of hypovirulence induced by a mycovirus in R. solani.

Diversity of Mycoviruses Present in Strains of Binucleate Rhizoctonia and Multinucleate Rhizoctonia, Causal Agents for Potato Stem Canker or Black Scurf

“…The family Partitiviridae contains five genera, namely Alphapartitivirus , Betapartitivirus , Gammapartitivirus , Deltapartitivirus , and Cryspovirus [ 19 , 64 ]. Recently, more and more unclassified partitiviruses previously were identified and proposed to be clustered into two new genera, Epsilonpartitivirus and Zetapartitivirus.…”

“…It was documented that Rhizoctonia hosted more than 100 mycoviruses, and most of them were isolated from multinucleate Rhizoctonia (MNR, whose nuclei per cell are at least three) (including R. solani anastomosis group (AG)-1, AG-2, AG-3 PT, and AG-4) and belonged to 8 families, namely Partitiviridae , Mitoviridae , Narnaviridae , Endornaviridae , Hypoviridae , Totiviridae , Bunyaviridae and Fusariviridae , and a proposed family Bipartitiviridae [ 3 , 15 , 16 , 17 , 18 , 19 , 20 ]. Only twelve mycoviruses were found in binucleate Rhizoctonia (BNR, whose nuclei per cell are two) including AG-Ba ( R. fumigate ), AG-DΙ ( R. cerealis ), and AG-Bb ( R. oryzae-sativae ), and belonged to four families ( Partitiviridae , Megabirnaviridae , Endornaviridae, and Mitoviridae ) and a proposed family Bipartitiviridae [ 15 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

Characterization of the First Alternavirus Identified in Fusarium avenaceum, the Causal Agent of Potato Dry Rot

“…Additionally, a FaAV1-free strain of F. avenaceum derived from strain GS-WW-224 was also used in the study. The FaAV1-free strain of F. avenaceum , designated as GS-WW-224-VF, was obtained by eliminating the mycovirus FaAV1 from strain GS-WW-224 using the hyphal tipping technique [ 38 , 39 ]. All twelve of the indicated Fusarium strains were cultured on potato dextrose agar (PDA) plates in the dark at 25 °C for seven days prior to their use.…”

A Botybirnavirus Isolated from Alternaria tenuissima Confers Hypervirulence and Decreased Sensitivity of Its Host Fungus to Difenoconazole

“…Reads mapped to the genome were utilized to determine the expression of each gene in each sample. Annotation of unigenes was performed using the databases described in our previous study [ 49 ]. Differentially expressed genes (DEGs) were identified using DESeq [ 50 ] software, which utilized statistical methods based on a negative binomial distribution model.…”

“…Differentially expressed genes (DEGs) were identified using DESeq [ 50 ] software, which utilized statistical methods based on a negative binomial distribution model. DEGs were designated as genes whose expression had a |log 2 fold-change| > 1 and a false discovery rate (FDR), as well as an adjusted p -value < 0.05 [ 49 ].…”