scholarly journals Specific and Common Alterations in Host Gene Transcript Accumulation following Infection of the Chestnut Blight Fungus by Mild and Severe Hypoviruses

2004 ◽  
Vol 78 (8) ◽  
pp. 4145-4155 ◽  
Author(s):  
Todd D. Allen ◽  
Donald L. Nuss
Keyword(s):  
Transcriptional Response ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Gene Transcript ◽  
Transcript Accumulation ◽  
Transcriptional Responses ◽  
Chestnut Blight Fungus ◽  
Reverse Transcription Pcr ◽  
Initial Assignment ◽  
Severe Isolate

ABSTRACT We report the use of a cDNA microarray to monitor global transcriptional responses of the chestnut blight fungus, Cryphonectria parasitica, to infection by mild and severe isolates of virulence-attenuating hypoviruses that share 87 to 93% and 90 to 98% identity at the nucleotide and amino acid levels, respectively. Infection by the mild hypovirus isolate CHV1-Euro7 resulted in differential expression of 166 of the ca. 2,200 genes represented on the microarray (90 upregulated and 76 downregulated). This is roughly half the number of genes scored as differentially expressed after infection by the severe isolate, CHV1-EP713 (295 genes; 132 upregulated and 163 downregulated). Comparison of the lists of genes responsive to infection by the two hypovirus isolates revealed 80 virus-common responsive genes. Infection by CHV1-EP713 also caused changes in gene transcript accumulation that were, in general, of greater magnitude than those observed with CHV1-Euro7 infections. Thus, the host transcriptional response to infection by severe hypovirus CHV1-EP713 appears to be considerably more dynamic than the response to infection by the mild isolate CHV1-Euro7. Real-time reverse transcription-PCR was performed on 39 different clones, with false-positive rates of 3 and 8% observed for the microarray-predicted list of genes responsive to CHV1-EP713 and CHV1-Euro7 infections, respectively. This analysis has allowed an initial assignment for ca. 2,200 unique C. parasitica-expressed genes as being unresponsive to hypovirus infection, selectively responsive to a specific hypovirus, or generally responsive to hypovirus infection.

scholarly journals Use of cDNA Microarrays To Monitor Transcriptional Responses of the Chestnut Blight FungusCryphonectria parasiticato Infection by Virulence-Attenuating Hypoviruses

2003 ◽  
Vol 2 (6) ◽  
pp. 1253-1265 ◽  
Author(s):  
Todd D. Allen ◽  
Angus L. Dawe ◽  
Donald L. Nuss
Keyword(s):  
Stress Responses ◽  
Transcript Abundance ◽  
Cryphonectria Parasitica ◽  
Northern Analysis ◽  
Chestnut Blight ◽  
Transcriptional Responses ◽  
Chestnut Blight Fungus ◽  
Reverse Transcription Pcr ◽  
Validation Rate ◽  
Microarray Studies

Hypoviruses are a family of cytoplasmically replicating RNA viruses of the chestnut blight fungusCryphonectria parasitica. Members of this mycovirus family persistently alter virulence (hypovirulence) and related fungal developmental processes, including asexual and sexual sporulation. In order to gain a better understanding of the molecular basis for these changes, we have developed aC. parasiticacDNA microarray to monitor global transcriptional responses to hypovirus infection. In this report, a spotted DNA microarray representing approximately 2,200C. parasiticagenes was used to monitor changes in the transcriptional profile after infection by the prototypic hypovirus CHV1-EP713. Altered transcript abundance was identified for 295 clones (13.4% of the 2,200 unique cDNAs) as a result of CHV1-EP713 infection—132 up-regulated and 163 down-regulated. In comparison, less than 20 specificC. parasiticagenes were previously identified by Northern analysis and mRNA differential display as being responsive to hypovirus infection. A 93% validation rate was achieved between real-time reverse transcription-PCR results and microarray predictions. Differentially expressed genes represented a broad spectrum of biological functions, including stress responses, carbon metabolism, and transcriptional regulation. These findings are consistent with the view that infection by a 12.7-kbp hypovirus RNA results in a persistent reprogramming of a significant portion of theC. parasiticatranscriptome. The potential impact of microarray studies on current and future efforts to establish links between hypovirus-mediated changes in cellular gene expression and phenotypes is discussed.

scholarly journals Linkage between Mitochondrial Hypovirulence and Viral Hypovirulence in the Chestnut Blight Fungus Revealed by cDNA Microarray Analysis

2004 ◽  
Vol 3 (5) ◽  
pp. 1227-1232 ◽  
Author(s):  
Todd D. Allen ◽  
Donald L. Nuss
Keyword(s):  
Mitochondrial Dysfunction ◽  
Cdna Microarray ◽  
Gene List ◽  
Chestnut Blight ◽  
Cdna Clones ◽  
Mtdna Mutation ◽  
Transcript Accumulation ◽  
Transcriptional Responses ◽  
Chestnut Blight Fungus ◽  
Virulence Attenuation

ABSTRACT The phenomenon of transmissible hypovirulence (virulence attenuation) associated with biological control of natural populations of the chestnut blight fungus Cryphonectria parasitica can be experimentally reproduced by infection with hypovirus cDNA clones (viral hypovirulence) or by mutation of mitochondrial DNA (mtDNA) in the absence of virus infection (mitochondrial hypovirulence). We now report the use of an established C. parasitica cDNA microarray to monitor nuclear transcriptional responses to an mtDNA mutation of C. parasitica strain EP155, designated EP155/mit2, which was previously shown to induce elevated alternative oxidase activity and hypovirulence (C. B. Monterio-Vitorello, J. A. Bell, D. W. Fulbright, and H. A. Bertrand, Proc. Natl. Acad. Sci. USA 92:5935-5939, 1995). Approximately 10% of the 2,200 genes represented on the microarray exhibited altered transcript accumulation as a result of the mit2 mtDNA mutation. While genes involved in mitochondrial function were clearly represented in the EP155/mit2-responsive gene list, direct parallels to the well-characterized Saccharomyces cerevisiae retrograde response to mitochondrial dysfunction were not observed. Remarkably, 47% of the genes that were differentially expressed following the infection of strain EP155 by the prototypic hypovirus CHV1-EP713 had similarly changed transcript accumulation in the virus-free EP155/mit2 mutant. These results establish a linkage between viral and mitochondrial hypovirulence and raise questions regarding the relationship between hypovirus infection and mitochondrial dysfunction. The combined set of transcriptional profile data provides a foundation for future studies on mitochondrion-to-nucleus communications in the context of hypovirus infection and senescence associated with mitochondrial dysfunction in filamentous fungi.

scholarly journals Comparative Analysis of Alterations in Host Phenotype and Transcript Accumulation following Hypovirus and Mycoreovirus Infections of the Chestnut Blight Fungus Cryphonectria parasitica

2007 ◽  
Vol 6 (8) ◽  
pp. 1286-1298 ◽  
Author(s):  
Fuyou Deng ◽  
Todd D. Allen ◽  
Bradley I. Hillman ◽  
Donald L. Nuss
Keyword(s):  
Expressed Sequence Tag ◽  
Signal Transduction Pathway ◽  
Strain Analysis ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Transcript Accumulation ◽  
Fungal Virulence ◽  
Regulatory Pathways ◽  
Phenotypic Changes ◽  
Chestnut Blight Fungus

ABSTRACT Infection of the chestnut blight fungus, Cryphonectria parasitica, by hypovirus CHV1-EP713 or by reovirus MyRV1-Cp9B21 or MyRV2-CpC18 results in reduced fungal virulence (hypovirulence). However, additional phenotypic changes caused by the two groups of mycoviruses are quite different. We now report that the loss of female fertility and the resulting absence of virus transmission through sexual spores observed after hypovirus infection was not observed for reovirus-infected C. parasitica. Consistent with this result, expression of two genes involved in sexual reproduction, the pheromone precursor gene, Mf2/1, and the yeast STE12-like transcriptional factor gene, cpst12, was less reduced in reovirus-infected strains than in the hypovirus CHV1-EP713-infected strain. Analysis with a custom microarray cDNA chip containing expressed sequence tag clones representing approximately 2,200 unique C. parasitica genes identified 140 and 128 host genes that were responsive to MyRV1-Cp9B21 or MyRV2-CpC18 infection, respectively. Comparison of these virus-responsive genes revealed an overlap of 85 genes, even though the nucleotide sequence identity for the two reoviruses is less than 50%. Significantly, 84 of the 85 genes were altered in the same direction. Further comparison revealed that 51% and 48% of the MyRV1-Cp9B21- and MyRV2-CpC18-responsive genes were also responsive to CHV1-EP713 infection. Finally, similar to results reported for CHV1-EP713 infection, a high percentage (59% and 66%) of the reovirus-responsive genes were also differentially expressed following disruption of the cellular G-protein signal transduction pathway. These data support the hypothesis that hypovirus and reovirus infections perturb common and specific C. parasitica regulatory pathways to cause hypovirulence and distinct sets of phenotypic changes.

Crypt1, an active Ac-like transposon from the chestnut blight fungus, Cryphonectria parasitica

2001 ◽  
Vol 265 (4) ◽  
pp. 730-738 ◽  
Author(s):  
D. Linder-Basso ◽  
R. Foglia ◽  
P. Zhu ◽  
B.I. Hillman
Keyword(s):  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus

scholarly journals Hard Mast Production Before and After the Chestnut Blight

2000 ◽  
Vol 24 (4) ◽  
pp. 196-201 ◽  
Author(s):  
Seth J. Diamond ◽  
Robert H. Giles ◽  
Roy L. Kirkpatrick ◽  
Gary J. Griffin
Keyword(s):  
Carrying Capacity ◽  
Basal Area ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
Chestnut Blight ◽  
Wildlife Species ◽  
Chestnut Blight Fungus ◽  
Southern Appalachian ◽  
Before And After ◽  
Mast Production

Abstract We estimated hard mast production of a Southern Appalachian forest for two 10 yr intervals: one before and one, 35 yr after, the chestnut blight fungus (Cryphonectria parasitica) (Murr.) Barr, had killed all mature chestnut trees. The basal area of hard mast-producing trees in the postblight forest was 28% less than in the preblight forest. The estimate of hard mast output was 34% less after the chestnut blight. Postblight production was less than preblight production for 8 of 10 yr. During 5 of these years, postblight production was only 5-27% of preblight production. Annual preblight mast production was relatively stable, whereas annual postblight production fluctuated substantially. Our findings suggest that the loss of mature chestnuts (Castanea dentata) markedly reduced the Southern Appalachian forest's carrying capacity for certain wildlife species. South. J. Appl. For 24(4):196-201.

scholarly journals Characterization of Hypovirus-Derived Small RNAs Generated in the Chestnut Blight Fungus by an Inducible DCL-2-Dependent Pathway

2008 ◽  
Vol 82 (6) ◽  
pp. 2613-2619 ◽  
Author(s):  
Xuemin Zhang ◽  
Gert C. Segers ◽  
Qihong Sun ◽  
Fuyou Deng ◽  
Donald L. Nuss
Keyword(s):  
Small Rnas ◽  
Rna Silencing ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Fungal Host ◽  
Chestnut Blight Fungus ◽  
Mutant Strains ◽  
Suppressor Of Rna Silencing ◽  
Dependent Pathway

ABSTRACT The disruption of one of two dicer genes, dcl-2, of the chestnut blight fungus Cryphonectria parasitica was recently shown to increase susceptibility to mycovirus infection (G. C. Segers, X. Zhang, F. Deng, Q. Sun, and D. L. Nuss, Proc. Natl. Acad. Sci. USA 104:12902-12906, 2007). We now report the accumulation of virus-derived small RNAs (vsRNAs) in hypovirus CHV1-EP713-infected wild-type and dicer gene dcl-1 mutant C. parasitica strains but not in hypovirus-infected dcl-2 mutant and dcl-1 dcl-2 double-mutant strains. The CHV1-EP713 vsRNAs were produced from both the positive and negative viral RNA strands at a ratio of 3:2 in a nonrandom distribution along the viral genome. We also show that C. parasitica responds to hypovirus and mycoreovirus infections with a significant increase (12- to 20-fold) in dcl-2 expression while the expression of dcl-1 is increased only modestly (2-fold). The expression of dcl-2 is further increased (∼35-fold) following infection with a hypovirus CHV1-EP713 mutant that lacks the p29 suppressor of RNA silencing. The combined results demonstrate the biogenesis of mycovirus-derived small RNAs in a fungal host through the action of a specific dicer gene, dcl-2. They also reveal that dcl-2 expression is significantly induced in response to mycovirus infection by a mechanism that appears to be repressed by the hypovirus-encoded p29 suppressor of RNA silencing.

scholarly journals Investigation of Host Range of and Host Defense against a Mitochondrially Replicating Mitovirus

2019 ◽  
Vol 93 (6) ◽  
Author(s):  
Sabitree Shahi ◽  
Ana Eusebio-Cope ◽  
Hideki Kondo ◽  
Bradley I. Hillman ◽  
Nobuhiro Suzuki
Keyword(s):  
Rna Polymerase ◽  
Host Range ◽  
Protoplast Fusion ◽  
Rna Silencing ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Rna Dependent Rna Polymerase ◽  
Content Type ◽  
Host Interactions ◽  
Chestnut Blight Fungus

ABSTRACT Mitoviruses (genus Mitovirus, family Narnaviridae) are mitochondrially replicating viruses that have the simplest positive-sense RNA genomes of 2.2 to 4.4 kb with a single open reading frame (ORF) encoding an RNA-dependent RNA polymerase. Cryphonectria parasitica mitovirus 1 (CpMV1) from U.S. strain NB631 of the chestnut blight fungus, Cryphonectria parasitica, was the first virus identified as a mitochondrially replicating virus. Despite subsequent discovery of many other mitoviruses from diverse fungi, no great advances in understanding mitovirus biology have emerged, partly because of the lack of inoculation methods. Here we developed a protoplast fusion-based protocol for horizontal transmission of CpMV1 that entailed fusion of recipient and donor protoplasts, hyphal anastomosis, and single-conidium isolation. This method allowed expansion of the host range to many other C. parasitica strains. Species within and outside the family Cryphonectriaceae, Cryphonectria radicalis and Valsa ceratosperma, also supported the replication of CpMV1 at a level comparable to that in the natural host. No stable maintenance of CpMV1 was observed in Helminthosporium victoriae. PCR-based haplotyping of virus-infected fungal strains confirmed the recipient mitochondrial genetic background. Phenotypic comparison between CpMV1-free and -infected isogenic strains revealed no overt effects of the virus. Taking advantage of the infectivity to the standard strain C. parasitica EP155, accumulation levels were compared among antiviral RNA silencing-proficient and -deficient strains in the EP155 background. Comparable accumulation levels were observed among these strains, suggesting the avoidance of antiviral RNA silencing by CpMV1, which is consistent with its mitochondrial replication. Collectively, the results of study provide a foundation to further explore the biology of mitoviruses. IMPORTANCE Capsidless mitoviruses, which are ubiquitously detected in filamentous fungi, have the simplest RNA genomes of 2.2 to 4.4 kb, encoding only RNA-dependent RNA polymerase. Despite their simple genomes, detailed biological characterization of mitoviruses has been hampered by their mitochondrial location within the cell, posing challenges to their experimental introduction and study. Here we developed a protoplast fusion-based protocol for horizontal transfer of the prototype mitovirus, Cryphonectria parasitica mitovirus 1 (CpMV1), which was isolated from strain NB631 of the chestnut blight fungus (Cryphonectria parasitica), a model filamentous fungus for studying virus-host interactions. The host range of CpMV1 has been expanded to many different strains of C. parasitica and different fungal species within and outside the Cryphonectriaceae. Comparison of CpMV1 accumulation among various RNA silencing-deficient and -competent strains showed clearly that the virus was unaffected by RNA silencing. This study provides a solid foundation for further exploration of mitovirus-host interactions.

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