Eucalypts Are Susceptible to the Chestnut Blight Fungus, Cryphonectria Parasitica

1988 ◽  
Vol 36 (5) ◽  
pp. 599 ◽  
Author(s):  
KM Old ◽  
T Kobayashi
Keyword(s):  
Eucalyptus Camaldulensis ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Castanea Crenata ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica ◽  
Accidental Introduction

Eucalyptus camaldulensis, E. haemastoma, E, microcorys, E. punctata and E. robusta grown in greenhouses in Japan were susceptible to infection by Cryphonectria parasitica, syn. Endothia parasitica. A Cryphonectria sp. found on Eucalyptus in central Honshu was morphologically identical to C. parasitica and caused cankers on the five eucalypts and Castanea crenata. Endothiella, the anamorph of Cryphonectria. spp, and Endothia spp., was found on eucalypts in four field locations in Honshu. The evidence suggests that eucalypts are infected in the field by C. parasitica in Japan. Accidental introduction of the chestnut blight fungus into Australia could have serious consequences for the health of native eucalypts, in addition to causing disease of cultivated chestnuts.

Population biology of the chestnut blight fungus, Cryphonectria parasitica

1995 ◽  
Vol 73 (S1) ◽  
pp. 311-319 ◽  
Author(s):  
Michael G. Milgroom
Keyword(s):  
Gene Flow ◽  
North America ◽  
Population Biology ◽  
Random Mating ◽  
Cryphonectria Parasitica ◽  
Vegetative Compatibility ◽  
Chestnut Blight ◽  
Vegetative Compatibility Groups ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica

Interest in the population biology of the chestnut blight fungus Cryphonectria parasitica has been motivated largely by the potential for biological control of chestnut blight with fungal viruses that cause hypovirulence. Earlier studies gave valuable insights into the correlation between diversity of vegetative compatibility groups and transmission of hypovirulence viruses. However, inferences about evolutionary processes affecting populations were not possible because vegetative compatibility groups are not genetically defined. Using restriction fragment length polymorphism markers, however, progress has been made in studying the origin of C. parasitica in North America, gene flow among populations, dispersal within populations, and recombination and the mating system. Cryphonectria parasitica populations in North America are genetically more similar to populations in Japan than in China, which is consistent with previous speculations that this fungus was introduced from Japan. Populations in China and Japan are quite different, suggesting little or no gene flow between these areas. Restricted gene flow and genetic drift are probably the dominant evolutionary forces shaping North American populations, with approximately 20% of gene diversity due to differences among populations (GST = 0.20). Two populations of C. parasitica in Michigan and one population in Italy are primarily clonal in structure. In contrast, sexual reproduction appears to be common in populations in eastern North America, although most of these populations deviate significantly from random mating. Deviations from random mating are most likely due to self-fertilization (uniparental inbreeding), restricted dispersal of male gametes, and mating between individuals that are more closely related genetically than would be expected by chance (biparental inbreeding). Aggregations of similar genotypes in space suggest that populations of C. parasitica may be structured into genetic neighborhoods by restricted dispersal. Future research efforts in this system will explore isolation by distance and address questions of hypovirulence virus coevolution with its fungal host. Key words: Cryphonectria parasitica, Endothia parasitica, chestnut blight, genetic neighbourhoods, inbreeding.

Spatial pattern analysis of vegetative compatibility groups in the chestnut blight fungus, Cryphonectria parasitica

1991 ◽  
Vol 69 (7) ◽  
pp. 1407-1413 ◽  
Author(s):  
Michael G. Milgroom ◽  
William L. MacDonald ◽  
Mark L. Double
Keyword(s):  
Average Distance ◽  
Cryphonectria Parasitica ◽  
Mantel Test ◽  
Vegetative Compatibility ◽  
Chestnut Blight ◽  
Spatial Pattern Analysis ◽  
Vegetative Compatibility Groups ◽  
Clear Cut ◽  
Chestnut Blight Fungus ◽  
Endothia Parasitica

Vegetative compatibility groups were determined for 914 isolates of the chestnut blight fungus, Cryphonectria (Endothia) parasitica, collected over a 5-year period from American chestnut trees in eight regenerating clear-cut plots. We tested the hypothesis that the average distance between individuals in the same vegetative compatibility group is not different from the average distance between individuals with vegetative compatibility assigned at random. Nonrandom patterns were detected in all plots at least once during the study, indicating that vegetative compatibility groups were often aggregated. However, when multiple occurrences of vegetative compatibility groups on the same tree were eliminated from the analysis, there was only one test (out of 98 in total) in which the null hypothesis was rejected. We conclude that nonrandom patterns of vegetative compatibility groups are due primarily to multiple occurrences of vegetative compatibility groups on the same trees. Nearly half of all new cankers detected once the epidemic got started were in the same vegetative compatibility groups as cankers previously resident on the same tree. These data are consistent with the hypothesis that populations of C. parasitica are partly clonal in structure. Key words: Endothia parasitica, hypovirulence, Mantel test, matrix comparison, spatial autocorrelation.

scholarly journals Detection of natural infection of Quercus spp. by the chestnut blight fungus (Cryphonectria parasitica) in Hungary

2002 ◽  
Vol 8 (2) ◽  
Author(s):  
L. Radócz ◽  
I. J. Holb
Keyword(s):  
Natural Infection ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
European Chestnut ◽  
Total Destruction ◽  
Quercus Spp ◽  
Endothia Parasitica

The chestnut blight fungus Cryphonectria parasitica (Murrill) Barr [syn.: Endothia parasitica (Murr) Anderson] caused almost total destruction of the American chestnut (Castanea dentata) and widely spread on European chestnut (Castanea saliva) in many European countries. In Hungary, because this fungus threatens most of the Hungarian chestnut stands, great efforts have been made to delay its spread. Biological control with Hungarian hypovirulent strains of the pathogen seems to be an effective method for saving the affected chestnut trees. Until 1998 the fungus was detected on Castanea saliva only, then on some trees of young Quercus petrea in mixed chestnut forests, which also showed the typical symptoms of blight (Kőszeg and Zengővárkony). Although blight symptoms are not so serious in Quercus spp. than in Castanea spp., it seems that C. parasitica threatens the young Quercus spp. in Hungary, mainly in heavily infected chestnut forests. This is the first report of C. parasitica cankers on oak in Hungary.

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 The Morphology and the Biological Control of Cryphonectria parasitica

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Carmen Emilia PUIA ◽  
Daniela Andreea GRIGORESCU ◽  
Raluca Vasilica MICLEA
Keyword(s):  
Biological Control ◽  
Virulent Strain ◽  
Morphological Characteristics ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Dual Culture ◽  
Natural Form ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Cryphonectria parasitica  (Murr.) Bar [syn. Endothia parasitica (Murr. And.] (anamorf: Endothiella sp .) is the causal agent of chestnut bark disease or chestnut blight, disease which produced great damages throughout the world, for example, in Europe, the European chestnut tree ( Castanea sativa (P.) Mill) was heavily affected. Environmental concerns have focused attention on natural forms of disease control as an effective alternative to chemical pesticides. In the chestnut blight fungus, Cryphonectria parasitica deals with a natural form of biological control in which the virulence of a fungal pathogen is attenuated by an endogenous viral RNA genetic element- the hypovirulent strain. In our researches we picked samples of chestnut bark from different areas in Maramures county. We’ve isolated the fungus on PDA medium and we’ve studied the morphological characteristics of the usual virulent strain and we looked for a possible hypovirulent strain in order to study its capacity for biological control. The fungus develops in the bark and in cambium where forms a yellowish or brownish stroma and produces both conidia and ascospores. The pycnidia stromata break through the lenticels producing conidia and later in the same stroma develop the perithecia which produce ascospores. Both strains of the fungus were found in the research area. The hypovirulent strain had a slower development, showed no sporu lation and pigmentation “white cultural strain” and was tested in vitro for the capacity to convert the virulent isolates by dual culture tests.

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.

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