scholarly journals Genetic diversity of Cryphonectria parasitica causing chestnut blight in South Tyrol (northern Italy)

2022 ◽  
Author(s):  
Farooq Ahmad ◽  
Sanja Baric
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Northern Italy ◽  
Chestnut Blight ◽  
Type Locus ◽  
South Tyrol ◽  
Its Sequence Analysis ◽  
Hyphal Anastomosis

AbstractEuropean chestnut (Castanea sativa) is threatened by the invasive fungus Cryphonectria parasitica, which causes chestnut blight. The virulence of the fungus can be reduced by a group of mycoviruses that can spread among vegetatively compatible strains through hyphal anastomosis. Hypovirulent isolates are used as biocontrol agents, but their efficiency can be diminished by restricted hyphal anastomosis if the variability of vegetative compatibility (vc) types in a population is high. Sexual reproduction could increase the vc type diversity and further complicate biocontrol in a region. Therefore, knowledge of genetic diversity of C. parasitica is important to assess the effectiveness of a biological control program. The present study was performed in the Autonomous Province of Bozen-Bolzano (South Tyrol) in northern Italy, where chestnut cultivation provides an additional income to farmers. The genetic characterization of C. parasitica isolates from 35 chestnut stands and one forest population in different districts of South Tyrol was performed based on the analysis of vegetative incompatibility loci, the mating type locus, and the internal transcribed spacer (ITS) region. In this study, a total of 23 different vc types were found all over South Tyrol with a Shannon diversity index of 1.86. EU-2, EU-1, and EU-13 were the most widespread vc types comprising 51%, 13%, and 9% of the fungal isolates, respectively. Both mating types were present in the region with a ratio close to 1:1. Three different haplotypes were identified based on ITS sequence analysis, which pointed to two introduction events of the fungus to the region and allowed placing C. parasitica from South Tyrol into a larger phylogeographic context.

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 Changes in Cryphonectria parasitica Populations Affect Natural Biological Control of Chestnut Blight

2018 ◽  
Vol 108 (7) ◽  
pp. 870-877 ◽  
Author(s):  
Marin Ježić ◽  
Jelena Mlinarec ◽  
Rosemary Vuković ◽  
Zorana Katanić ◽  
Ljiljana Krstin ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Infected Plant ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Native Plant ◽  
Native Plant Species ◽  
Sweet Chestnut ◽  
Tripartite Interactions ◽  
Disease Management Strategy

Invasive species, especially plant pathogens, have a potential to completely eradicate native plant species and remodel landscapes. Tripartite interactions among sweet chestnut (Castanea sativa), chestnut blight-causing invasive fungus Cryphonectria parasitica, and hyperparasitic virus Cryphonectria hypovirus 1 (CHV1) were studied in two populations. The number of different vegetative compatibility (vc) types of C. parasitica more than doubled over the 10 years, while the hypovirulence incidence dropped in one population and slightly increased in the other one. Over the course of our 3-year monitoring experiment, the prevalence of hypovirulent isolates obtained from monitored cankers increased slowly (i.e., more hypovirulent isolates were being obtained from the same cankers over time). Within studied cankers, considerable changes in vc type and CHV1 presence were observed, indicating a highly dynamic system in which virulent and hypovirulent mycelia, sometimes of discordant vc types, often appeared together. The increase in hypovirulence prevalence did not have any observable curative effect on the cankers and, occasionally, reactivation of healed cankers by new, virulent C. parasitica isolates was observed. Both short- and long-term observations and revalidation of the infected plant populations are necessary to accurately estimate disease progress and formulate an adequate disease management strategy.

scholarly journals New finds of Cryphonectria parasitica and the first record of chestnut blight on red oak Quercus rubra L. in the Czech Republic

2012 ◽  
Vol 51 (No. 6) ◽  
pp. 256-258 ◽  
Author(s):  
P. Haltofová ◽  
L. Jankovský ◽  
D. Palovčíková
Keyword(s):  
Czech Republic ◽  
Castanea Sativa ◽  
First Record ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Red Oak ◽  
The Czech Republic ◽  
Sweet Chestnut ◽  
New Localities ◽  
Endothia Parasitica

The causal agent of the chestnut blight, the fungus Cryphonectria parasitica (Murrill) M. E. Barr (syn. Endothia parasitica (Murrill) P. J. Anderson et H. W. Anderson), was found out at new localities in the Czech Republic. The chestnut blight was observed for the first time in the Czech Republic in 2002. Two new localities were discovered in southern Moravia in May and June 2004. The disease was identified both on the sweet chestnut (Castanea sativa Mill.) and on the red oak (Quercus rubraL.). Infected trees were treated according to the order of the State Phytosanitary Administration of the Czech Republic. 

scholarly journals Studies of Cryphonectria parasitica (MURR.) BARR subpopulations on Quercus petraea in Ukraine

2011 ◽  
pp. 70-75
Author(s):  
László Radócz ◽  
Gábor Tarcali ◽  
László Irinyi ◽  
Gábor Görcsös
Keyword(s):  
Fungal Pathogens ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Quercus Petraea ◽  
Carpathian Basin ◽  
Chestnut Blight ◽  
Oak Trees ◽  
Compatibility Group ◽  
Laboratory Examinations ◽  
Blight Disease

Chryphonectria parasitica (Murr.) Barr, the casual agent of chestnut blight disease, which is one of the most important fungal pathogens of chestnut (Castanea sativa). The disease seriously affected the chestnut in Northern-America and in Europe as well. It is important to mention that the pathogen does not only infect the chestnut but oak species (Quercus spp.) also. In the Carpathian-Basin, the chestnut is endemic in the Mecsek mountains, in Zala, in Somogy counties but it also can be found in the Danube-Bend. In the Carpathian-Basin (outside Hungary) the chestnut is found in Slovakia, Ukraine, Romania. In our study bark samples infected by Cryphonectria parasitica were collected from Bobovyshche, Serednje and Rostovjatica (Ukraine). The rate of infected chestnut tree were higher than 90% around Bobovyshche and beside chestnut, the symptoms were detected on oak trees as well. We collected bark samples from chestnut and oak as well and then we isolated the pathogen Cryphonectria parasitica in the lab of University of Debrecen. Symptomatological observations, laboratory examinations on fungus morphology, as well as comparisons of ITS sequency homology were made and approved that the causal agent of new disease was Cryphonectria parasitica. Our results proved that the Cryphonectria. parasitica infects oak trees beside chestnut in the Carpathian-Basin. Further studies are needed to determine the VCG (Vegatative Compatibility Group) group of the Cryphonectria parasitica found on oak trees. 

scholarly journals 065 Genetic Diversity of the Allegheny Chinkapin (Castanea pumila var. pumila)

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 452C-452
Author(s):  
Fenny Dane
Keyword(s):  
Genetic Diversity ◽  
Rapd Marker ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Disease Spread ◽  
Conservation Strategies ◽  
Chestnut Blight ◽  
Geographic Populations ◽  
Natural Range ◽  
Conservation Plan

American species in the genus Castanea are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. This disease spread throughout the natural range of the American chestnut and reduced the species from a timber and nut producing tree to an understory shrub. The lesser known member of the genus, the chinkapin, has also been affected by this disease and a conservation plan is needed. Genetic diversity within and between geographic populations of the Allegheny chinkapin was evaluated to provide baseline genetic information pertinent to conservation of the species. Nuts of Allegheny chinkapin trees from populations in Mississippi, Florida, Alabama, Virginia, and Ohio were collected and evaluated for isozyme and RAPD marker polymorphism. The genetic diversity of these populations will be compared with that of Ozark chinkapin and American chestnut populations. Conservation strategies will be discussed.

Genetic Diversity of Castanea pulia var. ozarkensis

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 526e-527
Author(s):  
Fenny Dane ◽  
Shona Harrison ◽  
Hongwen Huang
Keyword(s):  
Genetic Diversity ◽  
Cryphonectria Parasitica ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Ozark Highlands ◽  
The Past ◽  
Geographic Populations ◽  
Natural Range ◽  
Rapd Polymorphism ◽  
Taxonomic Studies

The genus Castanea includes several species, some of which, like the American chestnut (C. dentata) and chinkapin (C. pumila), are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. Blight spread throughout the natural range of the American chestnut, destroying several billion trees within the past 50 years. Although the plight of the American chestnut is well-known, the chinkapin has been neglected. Taxonomic studies indicated two varieties, the Ozark chinkapin, var. ozarkensis, limited to the Ozark Highlands of Arkansas, Missouri, and Oklahoma, and the Allegheny chinkapin, var. pumila, found from New Jersey to Florida and Texas. The genetic diversity within and between 11 geographic populations of the Ozark chinkapin was evaluated to provide baseline genetic information pertinent to the conservation and restoration of this species. Nuts or dormant buds of chinkapin trees were evaluated for isozyme and RAPD polymorphism. The genetic variability of the Ozark chinkapin populations was relatively high when compared to the American chestnut, and most of the diversity resides within the populations. Conservation considerations for restoration of the Ozark chinkapin will be discussed.

scholarly journals Management of Chestnut Blight in Greece Using Hypovirulence and Silvicultural Interventions

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 492 ◽  
Author(s):  
Stephanos Diamandis
Keyword(s):  
Biological Control ◽  
Castanea Sativa ◽  
Pilot Project ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Sweet Chestnut ◽  
Central Greece ◽  
Clear Cutting ◽  
Castanea Sativa Mill ◽  
Nut Production

Sweet chestnut (Castanea sativa Mill.) is an important tree for Greece. The invasive fungus Cryphonectria parasitica, which causes chestnut blight, was first found in Central Greece in 1963. It has since spread all over the country, significantly reducing the national annual nut production. The increasing decline of forests and orchards due to the disease led to a project in 1995, which aimed at studying the feasibility of applying biological control. A prerequisite study of the existing vegetative compatibility types of the pathogen showed only four, and their distribution was mapped. A pilot project (1998–2000) that consisted of clear cutting heavily infected coppice stands and introducing hypovirulence to the remainder was implemented on Mt. Athos on a 7000 ha sweet chestnut forest. Two evaluations (in 2003 and 2011) revealed that hypovirulence was established in the sweet chestnut forests and spread more or less homogeneously. A nationwide project introducing hypovirulence to 29 counties was implemented in two, 3-yr-periods 2007–2009 (17 counties) and 2014–2016 (12 counties). The new evaluations showed that hypovirulence spread profoundly and forests and orchards started recovering. The appearance of natural hypovirulence cannot be predicted. Introduced hypovirulence and silvicultural interventions can be used to manage the disease. It is the responsibility of the forest/orchard manager to decide whether to wait for appearance of natural hypovirulence, or to introduce it for a faster decline in disease.

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