Effect of dsRNA Associated with Isolates of<i>Cryphonectria parasitica</i>from the Central Appalachians and Their Relatedness to Other dsRNAs from North America and Europe

Enebak, Scott A.; MacDonald, William L.; Hillman, Bradley I.

doi:10.1094/phyto-84-528

Cited by 79 publications

(51 citation statements)

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“…A number of studies have evaluated the pathogenicity of fungi using the fastest-growing isolates in culture (Fulbright 1984, Brasier and Webber 1987, Enebak et al 1994. For example, Brasier and Webber (1987) reported a positive correlation between in vitro growth rate and pathogenicity of Ophiostoma ulmi, although this correlation was not consistent in all their experiments.…”

Section: Discussionmentioning

confidence: 99%

“…Inoculations on apples have been applied to reflect the relative pathogenicity of isolates of fungal pathogens (Fulbright 1984, Enebak et al 1994, de Lange et al 1998. Results obtained from the apple inoculation study showed a moderate to weak correlation with the pathogenicity results emerging from field inoculations.…”

Section: Discussionmentioning

confidence: 99%

“…Ideally, inoculations are made on healthy trees of the same species as those from which the pathogen was originally isolated, but this is a destructive process that is typically costly and time consuming because trees often need to be reared from seed or cuttings and they are relatively slow growing. Examples of techniques used for pathogenicity tests with tree pathogens include inoculation of branches or stems with agar plugs (Fulbright 1984, Enebak et al 1994 or gauze (Conradie et al 1992) on which the fungus has been cultured, or by injecting spore suspensions into artificially made wounds (Brasier andWebber 1987, Chongo andGossen 2001). Tests are either conducted under controlled conditions in a greenhouse, or under field conditions, depending on the availability of trees and the origin of the fungus to be tested.…”

Section: Introductionmentioning

confidence: 99%

“…Model systems for pathogenicity tests frequently use seedlings in greenhouses but these can result in low levels of correlation between field results and greenhouse experiments (Conradie et al 1992, van der Westhuizen et al 1992, Hong and Hwang 1998. Other characteristics, for example considering rate of growth in culture or inoculations on fruit such as apples (Fulbright 1984, Enebak et al 1994, de Lange et al 1998 have also been used to reflect pathogenicity of fungi, but these are valuable only if they are known to correlate with results from field tests.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

Wyk¹,

Heath²,

Tarigan³

et al. 2010

Southern Forests: a Journal of Forest Science

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Ceratocystis fimbriata sensu lato (s.l.) is an important pathogen of Eucalyptus. Pathogenicity of isolates has typically been evaluated by inoculating seedlings under greenhouse conditions. It is, however, not clear how accurately this reflects pathogenicity under field conditions. In this study, five techniques to potentially screen C. fimbriata isolates for their relative pathogenicity to Eucalyptus were compared. These included: in vitro growth comparisons on artificial media; inoculations on apples; inoculation on Eucalyptus seedlings in a greenhouse; inoculations on Eucalyptus bolts freshly cut from stems of young trees; and field inoculations on young trees. Eight isolates of C. fimbriata s.l. collected from various areas in South Africa were used. There was considerable variation in growth in culture and aggressiveness of the eight isolates. Field inoculations on young trees were best correlated with inoculations of bolts (r = 0.76). Lower correlation coefficients were obtained with seedlings (r = 0.59), apple inoculations (r = 0.56), and in vitro colony growth (r = 0.42). Inoculation of bolts provides a rapid and reliable method to screen isolates of C. fimbriata s.l. for pathogenicity to Eucalyptus.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

Wyk¹,

Heath²,

Tarigan³

et al. 2010

Southern Forests: a Journal of Forest Science

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“…The rate of mycovirus transmission through conidia is influenced by interactions between virus isolates, host fungal stains, and culture conditions (19,20). For example, the transmission efficiency of virus isolate CHV1-EP713 is 5% for infected fungal species C. radicalis and 86% for infected C. havanensis under benchtop conditions, and 100 and 66%, respectively, for the same fungal species under high light conditions (9).…”

Section: Vol 77 2003mentioning

confidence: 99%

Hypovirus Papain-Like Protease p29 Functions in trans To Enhance Viral Double-Stranded RNA Accumulation and Vertical Transmission

Suzuki

Maruyama

Moriyama

et al. 2003

J Virol

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The prototypic hypovirus CHV1-EP713 attenuates virulence (hypovirulence) and alters several physiological processes of the chestnut blight fungus Cryphonectria parasitica. The papain-like protease, p29, and the highly basic protein, p40, derived, respectively, from the N-terminal and C-terminal portions of the CHV1-EP713-encoded open reading frame (ORF) A polyprotein, p69, both contribute to reduced pigmentation and sporulation. The p29 coding region was shown to suppress pigmentation and asexual sporulation in the absence of virus infection in transformed C. parasitica, whereas transformants containing the p40-coding domain exhibited a wild-type, untransformed phenotype. Deletion of either p29 or p40 from the viral genome also results in reduced accumulation of viral RNA. We now show that p29, but not p40, functions in trans to enhance genomic RNA accumulation and vertical transmission of p29 deletion mutant viruses. The frequency of virus transmission through conidia was found to decrease with reduced accumulation of viral genomic double-stranded RNA (dsRNA): from almost 100% for wild-type virus to ϳ50% for ⌬p29, and 10 to 20% for ⌬p69. When expressed from a chromosomally integrated cDNA copy, p29 elevated viral dsRNA accumulation and transmission for ⌬p29 mutant virus to the level shown by wild-type virus. Increased viral RNA accumulation levels were also observed for a ⌬p69 mutant lacking almost the entire ORF A sequence. Such enhancements were not detected in transgenic fungal colonies expressing p40. Mutation of p29 residues Cys 70 or Cys 72 , strictly conserved in hypovirus p29 and potyvirus HC-Pro, resulted in the loss of both p29-mediated suppressive activity in virus-free transgenic C. parasitica and in trans enhancement of RNA accumulation and transmission, suggesting a linkage between these functional activities. These results suggest that p29 is an enhancer of viral dsRNA accumulation and vertical virus transmission through asexual spores.Members of the virus family Hypoviridae (22) persistently attenuate virulence (hypovirulence) and stably alter complex biological processes upon infection of their fungal host, the chestnut blight fungus, Cryphonectria parasitica. Infection-related phenotypic changes can include suppressed pigment production and asexual sporulation, altered colony morphology, loss of female fertility and modified expression of specific host genes (1,18,28,31). Infectious hypovirus cDNA clones (8, 10) and a robust transformation protocol for C. parasitica (15) provide a versatile system for identifying virus-encoded symptom determinants and modulators of hypovirus replication.Choi and Nuss (13) showed that transformation of virus-free C. parasitica with the 5Ј-proximal coding domain, open reading frame (ORF) A, resulted in suppressed conidiation and pigmentation but no change in fungal virulence. ORF A encodes a papain-like protease, p29, and a highly basic protein, p40, derived, respectively, from the N terminus and C terminus of polyprotein, p69, by a p29-mediated autocatalytic cl...

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The Ecology and Evolution of Fungal Viruses

Milgroom

Hillman

2011

Studies in Viral Ecology

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Effect of dsRNA Associated with Isolates ofCryphonectria parasiticafrom the Central Appalachians and Their Relatedness to Other dsRNAs from North America and Europe

Cited by 79 publications

References 0 publications

Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

Comparison of procedures to evaluate the pathogenicity of Ceratocystisfimbriata sensu lato isolates from Eucalyptus in South Africa

Hypovirus Papain-Like Protease p29 Functions in trans To Enhance Viral Double-Stranded RNA Accumulation and Vertical Transmission

The Ecology and Evolution of Fungal Viruses

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