Virus-associated down-regulation of the gene encoding cryparin, an abundant cell-surface protein from the chestnut blight fungus, Cryphonectria parasitica

Zhang, L.; Villalon, Deborah K.; Sun, Yeqing; Kazmierczak, Pam; Alfen, Neal K. Van

doi:10.1016/0378-1119(94)90523-1

Cited by 80 publications

(67 citation statements)

References 20 publications

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“…Sequences resembling CCAAT and TATA boxes are present in the 5' nontranscribed region of VWr2 (TATAAATA). These sequences show similarities with the promoter region of another highly expressed C. parasitica gene, that for cryparin (TATAAA) (57). The C. parasitica laccase gene also contains a similar TATA box sequence, TATATAAA (9).…”

Section: Discussionmentioning

confidence: 84%

“…Of the four ORFs present in the Vir2 transcribed sequence, the region 5' to the first ATG codon, TCAAA, fits most closely with this consensus sequence. The cryparin gene also contains a TCAAA sequence immediately upstream of the first ATG site, which has been shown to be the translation initiation site by protein N-terminal analysis (57). It is likely that this consensus sequence is also the site of translation initiation for the Vir2 gene.…”

Section: Discussionmentioning

confidence: 99%

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Hypovirulence-associated traits induced by a mycovirus of Cryphonectria parasitica are mimicked by targeted inactivation of a host gene.

et al. 1993

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Expression of the Vr2 gene of Cryphonectria parasitica is down-regulated in strains of the fungus containing a double-stranded RNA genetic element that reduces fungal virulence (W. A. Powell and N. K. Van Alfen, Mol. Cell. Biol. 7:3688-3693, 1987). We have sequenced the Vr2 gene and characterized its structure; the mRNA contains a short open reading frame whose product has structural similarities to several fungal pheromones. A null mutant was constructed by homologous recombination to determine the function of the Vr2 gene and whether its disruption resulted in any of the altered phenotypes exhibited by many hypovirulent strains, such as reductions in virulence, pigmentation, and sporulation. The Vr2 null mutant (18dm) exhibited a wild-type phenotype with respect to gross colony morphology, growth rate, pigmentation, asexual spore viability, and virulence in apple fruit and chestnut trees. However, numbers of asexual fruiting bodies (pycnidia) and conidia were reduced significantly in comparison with the wild-type strain EP155/2. In sexual crosses of 18dm with a wild-type strain of the opposite mating type, perithecia (sexual fruiting bodies) developed but were barren. Deletion of the Vr2 gene results in a phenotype that mimics that of many double-stranded-RNA-containing hypovirulent strains; i.e., the null mutant exhibits significant reductions in asexual sporulation and pycnidium production as well as impaired sexual crossing ability. To our knowledge, this is the first report of the partial reproduction of a virus-induced phenotype by deletion of a virus-perturbed host gene.The filamentous fungus Cryphonectnia (Endothia)parasitica (Murr.) Barr is responsible for the chestnut blight disease, which destroyed American chestnut forests over a 40-year period during the early part of this century (reviewed in references 3, 4, and 42). Biological control of C. parasitica and recovery of infected trees has occurred in Europe by the cytoplasmic transmission of double-stranded RNA (dsRNA) genetic elements between fungal strains. These virus-like elements typically confer a reduction in virulence (hypovirulence) to the fungus and are transmitted from hypovirulent to virulent strains during hyphal anastomosis (fusion of hyphae). In addition to hypovirulence, fungal strains harboring these genetic elements may exhibit an altered colony morphology that includes reduced sporulation and changes in pigmentation (21; reviewed in references 4, 33, 42, and 52). Reductions in levels of enzymes such as laccase (9,28,40,41) and cutinase (53) or of metabolites such as oxalate (27, 28) may also occur in hypovirulent strains. The phenomenon of cytoplasmically transmissible hypovirulence in C. parasitica is one of the best-documented examples of a naturally occurring form of biological control for plant disease. Our studies are directed towards understanding how dsRNA genetic elements in the fungus cause the attendant changes in host phenotype.The dsRNA virus-like elements associated with different hypovirulent strains of C. parasiti...

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Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Hypovirulence-associated traits induced by a mycovirus of Cryphonectria parasitica are mimicked by targeted inactivation of a host gene.

et al. 1993

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“…SCI, SC3, and SC4 are proteins from Schizophyllum commune (Wessels et al 1991); Eas, RodA, and SsgA are translated from genes of Aspergillus nidulans, Neurospora crassa (Bell-Pedersen et al 1992), and Metarhizium anisopliae (St. Leger et al 1992); cerato-ulmin (C.U.) 1s a toxin peptide from Ophiostorna ulmi (Stringer and Timberlake 1993); Cryparin (Crp) is a peptide from Cryphonectria parasitica (Zhang et al 1994). The sequences were aligned, as proposed by Stringer and Timberlake (1993), based on the conserved cysteine residues (shown in bold) using the SeqApp programme.…”

Section: Molecular Cloning Of Sr Fungal Genesmentioning

confidence: 99%

Fungal gene expression during ectomycorrhiza formation

Martin¹,

Praly²,

Carvalho³

et al. 1995

Can. J. Bot.

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Ectomycorrhiza development involves the differentiation of structurally specialized fungal tissues (e.g., mantle and Hartig net) and an interface between symbionts. Polypeptides presenting a preferential, up-, or down-regulated synthesis have been characterized in several developing ectomycorrhizal associations. Their spatial and temporal expressions have been characterized by cell fractionation, two-dimensional polyacrylamide gel electrophoresis. and immunochemical assays in the Eucalyptus spp. -Pisolithus tinctorius mycorrhizas. These studies have emphasized the importance of fungal cell wall polypeptides during the early stages of the ectomycorrhizal interaction. The increased synthesis of 30-to 32-kDa acidic polypeptides, together with the decreased accumulation of a prominent 95-kDa mannoprotein provided evidence for major alterations of Pisolithus tinctorius cell walls during mycorrhiza formation. Differential cDNA library screening and shotgun cDNA sequencing were used to clone symbiosis-regulated fungal genes. Several abundant transcripts showed a significant amino acid sequence similarity to a family of secreted morphogenetic fungal proteins, the so-called hydrophobins. In P. tinctorius, the content of hydrophobin transcripts is high in aerial hyphae and during the ectomycorrhizal sheath formation. Alteration of cell walls and the extracellular matrix is therefore a key event in the ectomycorrhiza development. An understanding of the molecular mechanisms that underlies the temporal and spatial control of genes and proteins involved in the development of the symbiotic interface is now within reach, as more sophisticated techniques of molecular and genetic analysis are applied to the mycorrhizal interactions.Key words: cell walls, ectomycorrhiza, ectomycorrhizins, fungal development, hydrophobins, symbiosisregulated polypeptides.RCsum6 : Le dkveloppement de la symbiose ectomycorhizienne implique la diffkrenciation de structures multicellulaires fongiques (le manteau et le reseau de Hartig) et la formation d'une interface spCcialiske entre symbiotes. Des polypeptides sp6cifiques de la symbiose (ectomycorhizincs) et des polypeptides dont la synthkse est modifiCe par le dkveloppement de l'ectomycorhize ont t t C mis en Cvidence dans plusieurs associations symbiotiques. L'expression spatio-temporelle de ces polypeptides rCgulCs par la symbiose a Ct C caract6risCe par fractionnement cellulaire, Clectrophorbse bidimensionnelle, et immunoquantification des proteines dans I'ectomycorhize d'Elrculyptus spp. -Pisolithus tinctorius. Ces Ctudes ont montre I'impact des premikres Ctapes de l'interaction mycorhizicnne sur la synthkse des polypeptides pariktaux du mycklium. Les modifications de la paroi fongique du basidiomyckte Pisolithus tirzctorius se manifestent par une stimulation de la synthkse de polypeptides acides de 30-32 kDa et, simultanCment, une chute de la biosynthbe d'une mannoprotkine majeure de 95 kDa. Des gknes fongiques rCgulCs par le dCveloppement de la symbiose ont et6 clonCs par hybridatio...

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“…C. parasitica strains containing the double-stranded (ds) RNA virus Cryphonectria hypovirus (CHV) display characteristic symptoms of hypovirulence and hypovirulence-associated changes such as reduced sporulation, laccase production, oxalate accumulation and pigmentation (Havir & Anagnostakis, 1983;Elliston, 1985;Rigling et al, 1989). Interestingly, the symptoms caused by hypoviral infection appear to be the result of aberrant expression of specific fungal genes in the hypovirulent strain, including genes for cutinase, laccase, cryparin and mating pheromones (Rigling & Van Alfen, 1991;Choi et al, 1992;Varley et al, 1992;Zhang et al, 1993Zhang et al, , 1994Allen et al, 2003;Allen & Nuss, 2004). Thus, C. parasitica and its hypovirus are a useful model system to study the mechanisms of fungal gene regulation by a mycovirus.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the ERK homologue CpMK2 from the chestnut blight fungus Cryphonectria parasitica

et al. 2005

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The Cryphonectria parasitica gene cpmk2, which encodes a mitogen-activated protein kinase belonging to the yeast extracellular signalling-regulated kinase (YERK1) subfamily, was isolated and its biological function was examined. Disruption of cpmk2 resulted in impaired pigmentation and abolished conidiation. Growth defects were observed in the cpmk2 mutant grown on solid plates, but growth of the mutant appeared normal in liquid media, including EP complete and PD broth, suggesting that the cpmk2 gene is involved in sensing and responding to growth conditions. The mutant's production of laccase, as measured by the size of the coloured area produced on tannic-acid-supplemented plates, was significantly reduced compared with the wild-type, but the intensity of the coloured area was unchanged, suggesting that the reduced laccase activity was owing to reduced growth on solid media rather than transcriptional downregulation. A dramatic reduction observed in the canker area produced by the cpmk2 mutant compared with the wild-type, even more severe than that of a hypovirulent strain, can also be ascribed to defective growth on solid surfaces rather than to impairments in a virulence factor(s). Downregulation of the pheromone gene Mf2/1 was also observed in the mutant, indicating a possible explanation for the regulation of the pheromone precursor gene in filamentous fungi and suggesting the presence of the yeast-like pheromone-responsive pathway in C. parasitica. Immunoblot analyses revealed that the phosphorylation level of CpMK2 increased in both virus-free and virus-containing strains in liquid cultures of up to 5 days old and decreased in older cultures. Moreover, the CpMK2 phosphorylation level increased in both strains after transfer from liquid to solid medium. However, levels of phosphorylated CpMK2 were similar in the two strains, suggesting that CpMK2, unlike CpMK1, is not under the direct control of a hypovirus.

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Virus-associated down-regulation of the gene encoding cryparin, an abundant cell-surface protein from the chestnut blight fungus, Cryphonectria parasitica

Cited by 80 publications

References 20 publications

Hypovirulence-associated traits induced by a mycovirus of Cryphonectria parasitica are mimicked by targeted inactivation of a host gene.

Hypovirulence-associated traits induced by a mycovirus of Cryphonectria parasitica are mimicked by targeted inactivation of a host gene.

Fungal gene expression during ectomycorrhiza formation

Characterization of the ERK homologue CpMK2 from the chestnut blight fungus Cryphonectria parasitica

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