scholarly journals First Report of Ectomycorrhizal Fungus, Laccaria ochropurpurea, Associated with Castanea dentata (American Chestnut) Roots in a Mixed-Species Plantation

2019 ◽  
Vol 20 (3) ◽  
pp. 140-141
Author(s):  
Morgan V. Ritzi ◽  
Stephen D. Russell ◽  
M. Catherine Aime ◽  
Gordon G. McNickle
Keyword(s):  
Cryphonectria Parasitica ◽  
Ectomycorrhizal Fungus ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Fungal Colonization ◽  
Root Tips ◽  
Mixed Species ◽  
Plant Host ◽  
Mutualistic Association ◽  
Direct Confirmation

American chestnut (Castanea dentata) is critically endangered by chestnut blight caused by Cryphonectria parasitica. Beneficial interactions with mutualistic ectomycorrhizae sometimes confer resistance to pathogens; however, little is known about the mycorrhizal partners of American chestnut. Basidiocarps of Laccaria ochropurpurea were observed in a 10-year-old American chestnut plantation. The identity of the species was confirmed utilizing the nuclear ribosomal internal transcribed spacer. In spring 2018, root fragments were excised from beneath three American chestnut trees in three separate plots where basidiocarps were observed. Root tips with evidence of mycorrhizal fungal colonization were pooled, extracted, and sequenced to confirm both the plant host and mycorrhizal associates. To our knowledge, this is the first direct confirmation of American chestnut roots associated with L. ochropurpurea. We suggest further studies to investigate whether this association is common, whether it confers any disease resistance, and if this mutualistic association could be employed in restoration efforts of the American chestnut.

scholarly journals Comparisons of Ectomycorrhizal Colonization of Transgenic American Chestnut with Those of the Wild Type, a Conventionally Bred Hybrid, and Related Fagaceae Species

2014 ◽  
Vol 81 (1) ◽  
pp. 100-108 ◽  
Author(s):  
Katherine M. D'Amico ◽  
Thomas R. Horton ◽  
Charles A. Maynard ◽  
Stephen V. Stehman ◽  
Allison D. Oakes ◽  
...  
Keyword(s):  
Cryphonectria Parasitica ◽  
Oxalate Oxidase ◽  
Fungal Species ◽  
American Chestnut ◽  
Fungal Colonization ◽  
Wild Type ◽  
Root Tips ◽  
Oxidase Gene ◽  
Content Type ◽  
Ectomycorrhizal Colonization

ABSTRACTAmerican chestnut (Castanea dentata[Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the chestnut blight,Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-resistant chestnut trees that could be released back into the native range. However, before such a release can be undertaken, it is necessary to assess nontarget impacts. Since oxalate oxidase is meant to combat a fungal pathogen, we are particularly interested in potential impacts of this transgene on beneficial fungi. This study compares ectomycorrhizal fungal colonization on a transgenic American chestnut clone expressing enhanced blight resistance to a wild-type American chestnut, a conventionally bred American-Chinese hybrid chestnut, and other Fagaceae species. A greenhouse bioassay used soil from two field sites with different soil types and land use histories. The number of colonized root tips was counted, and fungal species were identified using morphology, restriction fragment length polymorphism (RFLP), and DNA sequencing. Results showed that total ectomycorrhizal colonization varied more by soil type than by tree species. Individual fungal species varied in their colonization rates, but there were no significant differences between colonization on transgenic and wild-type chestnuts. This study shows that the oxalate oxidase gene can increase resistance againstCryphonectria parasiticawithout changing the colonization rate for ectomycorrhizal species. These findings will be crucial for a potential deregulation of blight-resistant American chestnuts containing the oxalate oxidase gene.

Ex situ conservation of American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), a review

2000 ◽  
Vol 76 (5) ◽  
pp. 765-774 ◽  
Author(s):  
Ken McIlwrick ◽  
S. Wetzel ◽  
T. Beardmore ◽  
K. Forbes
Keyword(s):  
Genetic Information ◽  
Ex Situ Conservation ◽  
In Situ Conservation ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Ex Situ ◽  
Juglans Cinerea ◽  
Research Areas

Two tree species native to North America, American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), which have experienced rapid declines in their populations due to similar stressors (disease and changes in land use), are used as examples of how these species would benefit from ex situ conservation efforts. Current and past ex situ and in situ conservation efforts for these species are discussed and the focus of this review is on two key research areas: 1) what needs to be preserved (genetic information) and 2) how to preserve these trees or germplasm. Key words: butternut, American chestnut, Cryphonectria parasitica, Sirococcus clavigignenti-juglandacearum, ex situ conservation

scholarly journals Resistance toPhytophthora cinnamomiin American Chestnut (Castanea dentata) Backcross Populations that Descended from Two Chinese Chestnut (Castanea mollissima) Sources of Resistance

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1631-1641 ◽  
Author(s):  
Jared W. Westbrook ◽  
Joseph B. James ◽  
Paul H. Sisco ◽  
John Frampton ◽  
Sunny Lucas ◽  
...  
Keyword(s):  
Phytophthora Cinnamomi ◽  
Seedling Survival ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Chestnut Blight ◽  
Sources Of Resistance ◽  
Backcross Population ◽  
Chinese Chestnut ◽  
Root Health

Restoration of American chestnut (Castanea dentata) depends on combining resistance to both the chestnut blight fungus (Cryphonectria parasitica) and Phytophthora cinnamomi, which causes Phytophthora root rot, in a diverse population of C. dentata. Over a 14-year period (2004 to 2017), survival and root health of American chestnut backcross seedlings after inoculation with P. cinnamomi were compared among 28 BC3, 66 BC4, and 389 BC3F3families that descended from two BC1trees (Clapper and Graves) with different Chinese chestnut grandparents. The 5% most resistant Graves BC3F3families survived P. cinnamomi infection at rates of 75 to 100% but had mean root health scores that were intermediate between resistant Chinese chestnut and susceptible American chestnut families. Within Graves BC3F3families, seedling survival was greater than survival of Graves BC3and BC4families and was not genetically correlated with chestnut blight canker severity. Only low to intermediate resistance to P. cinnamomi was detected among backcross descendants from the Clapper tree. Results suggest that major-effect resistance alleles were inherited by descendants from the Graves tree, that intercrossing backcross trees enhances progeny resistance to P. cinnamomi, and that alleles for resistance to P. cinnamomi and C. parasitica are not linked. To combine resistance to both C. parasitica and P. cinnamomi, a diverse Graves backcross population will be screened for resistance to P. cinnamomi, survivors bred with trees selected for resistance to C. parasitica, and progeny selected for resistance to both pathogens will be intercrossed.

scholarly journals A threshold level of oxalate oxidase transgene expression reduces Cryphonectria parasitica-induced necrosis in a transgenic American chestnut (Castanea dentata) leaf bioassay

2013 ◽  
Vol 22 (5) ◽  
pp. 973-982 ◽  
Author(s):  
Bo Zhang ◽  
Allison D. Oakes ◽  
Andrew E. Newhouse ◽  
Kathleen M. Baier ◽  
Charles A. Maynard ◽  
...  
Keyword(s):  
Transgene Expression ◽  
Threshold Level ◽  
Cryphonectria Parasitica ◽  
Oxalate Oxidase ◽  
Castanea Dentata ◽  
American Chestnut

scholarly journals Transformation of American Chestnut (Castanea dentata (Marsh.) Borkh) Using RITA® Temporary Immersion Bioreactors and We Vitro Containers

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1196
Author(s):  
Linda McGuigan ◽  
Patrícia Fernandes ◽  
Allison Oakes ◽  
Kristen Stewart ◽  
William Powell
Keyword(s):  
Liquid Medium ◽  
Phytophthora Cinnamomi ◽  
The United States ◽  
Pathogen Resistance ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Antifungal Protein ◽  
Semisolid Medium ◽  
Temporary Immersion

American chestnut (Castanea dentata (Marsh.) Borkh) was almost completely wiped out by the fungal pathogen, Cryphonectria parasitica (Murrill) M.E. Barr. Another invasive pathogen, Phytophthora cinnamomi Rands, is devastating American chestnuts in the southern region of the United States. An alternative approach for controlling these pathogens is to use genetic engineering or gene editing. We successfully transformed American chestnut with a detoxifying enzyme, oxalate oxidase, to enhance blight tolerance and more recently with the Cast_Gnk2-like gene, which encodes for an antifungal protein, to be tested for P. cinnamomi putative tolerance. Eight somatic embryo lines were transformed using three methods of selection: semisolid medium in Petri plates, liquid medium in RITA® temporary immersion bioreactors, or liquid medium in We Vitro containers. No significant differences were found between the treatments. These methods will allow for further testing of transgenes and the development of enhanced pathogen resistance in chestnut. It can serve as a model for other tree species threatened by invasive pests and pathogens.

scholarly journals REMNANT AMERICAN CHESTNUT (CASTANEA DENTATA (MARSH.) BORKH.; FAGACEAE) IN UPLAND FORESTS OF NORTHWESTERN NEW YORK

2016 ◽  
Author(s):  
Robert G. Laport
Keyword(s):  
New York ◽  
The United States ◽  
Cryphonectria Parasitica ◽  
Castanea Dentata ◽  
American Chestnut ◽  
Hardwood Species ◽  
Forested Areas ◽  
Identification And Characterization ◽  
Historical Range

AbstractThe American chestnut (Castanea dentata [Marsh.] Borkh.; Fagaceae) was an historically important hardwood species in eastern deciduous forests of the United States and Canada prior to being nearly eradicated by chestnut blight (Cryphonectria parasitica (Murr.) Barr). Several remnant populations have been identified persisting across fragmented parts of the historical range. The identification and characterization of remnant C. dentata populations is important for breeding and conservation efforts, as they may represent potential genetic sources of local adaptation or blight resistance, but much of the historical range remains unsurveyed. Here, I report the locations, blight infection status, and reproductive status of remnant American chestnut in upland forested areas of western New York, finding several reproductive/potentially reproductive trees.

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.

scholarly journals Genomic selection analyses reveal tradeoff between chestnut blight tolerance and genome inheritance from American chestnut (Castanea dentata) in (C. dentataxC. mollissima) xC. dentatabackcross populations

2019 ◽  
Author(s):  
Jared W. Westbrook ◽  
Qian Zhang ◽  
Mihir K. Mandal ◽  
Eric V. Jenkins ◽  
Laura E. Barth ◽  
...  
Keyword(s):  
Genomic Prediction ◽  
Prediction Models ◽  
Major Gene ◽  
Predictive Ability ◽  
Cryphonectria Parasitica ◽  
Major Effect ◽  
Castanea Dentata ◽  
American Chestnut ◽  
The Past ◽  
Type Form

AbstractAmerican chestnut was once a foundation species of eastern North American forests, but was rendered functionally extinct in the early 20th century by an exotic fungal blight (Cryphonectria parasitica). Over the past 30 years, The American Chestnut Foundation (TACF) has pursued backcross breeding to generate hybrids that combine the timber-type form of American chestnut with the blight tolerance of Chinese chestnut. The backcross strategy has been implemented based on the hypothesis that blight tolerance is conferred by few major effect alleles. We tested this hypothesis by developing genomic prediction models for five presence/absence blight phenotypes of 1,230 BC3F2selection candidates and average canker severity of their BC3F3progeny. We also genotyped pure Chinese and American chestnut reference panels to estimate the proportion of BC3F2genomes inherited from parent species. We found that genomic prediction from a method that assumes an infinitesimal model of inheritance (HBLUP) has a similar predictive ability to a method that tends to perform well for traits controlled by major genes (Bayes C). Furthermore, the proportion of BC3F2trees’ genomes inherited from American chestnut was negatively correlated with the blight tolerance of BC3F2trees and their progeny. On average, selected BC3F2trees inherited 83% of their genome from American chestnut and have blight-tolerance that is intermediate between F1hybrids and American chestnut. Results suggest polygenic rather than major gene inheritance for blight tolerance. The blight-tolerance of restoration populations will be enhanced by advancing additional sources of blight-tolerance through fewer backcross generations and by potentially by breeding with transgenic blight-tolerant trees.

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