Rescue of American chestnut with extraspecific genes following its destruction by a naturalized pathogen

  title={Rescue of American chestnut with extraspecific genes following its destruction by a naturalized pathogen},
  author={Kim C. Steiner and Jared W. Westbrook and Frederick V. Hebard and Laura L. Georgi and William A. Powell and Sara F. Fitzsimmons},
  journal={New Forests},
Following the near-obliteration of American chestnut (Castanea dentata [Marsh.] Borkh.) by the chestnut blight early in the last century, interest in its restoration has been revived by efforts to develop a blight-resistant form of the species. We summarize progress and outline future steps in two approaches: (1) a system of hybridizing with a blight-resistant chestnut species and then backcrossing repeatedly to recover the American type and (2) transformation of American chestnut with a… 
Intentional introgression of a blight tolerance transgene to rescue the remnant population of American chestnut
It will also be critically important that optimal restoration trees should have robust genetic diversity and resilience, which can be supplied by a full complement of their wild‐type genes.
Restoration of the American chestnut will require more than a blight-resistant tree.
The American chestnut (Castanea dentata) was a keystone species that was decimated by nonnative diseases, most notably a fungus (Cryphonectria parasitica) that causes chestnut blight disease, during
Supplemental materials for Beyond blight: Phytophthora root rot under climate change limits populations of reintroduced American chestnut
American chestnut ( Castanea dentata ) was functionally extirpated from eastern US forests by chestnut blight, caused by a fungus from Asia. As efforts to produce blight-resistant American chestnut
Pathogen‐induced expression of a blight tolerance transgene in American chestnut
Targeted expression of OxO to wounded and infected tissue is sought as an alternative to constitutive expression for potential metabolic resource conservation and transgene stability over the long lifetime of a tree and over successive generations of breeding.
Resurrecting the Lost Flames of American Chestnut
The loss of American chestnut may have altered litter flammability of some eastern US forest ecosystems, a result more commonly associated with compositional changes in conjunction with fire exclusion and other disturbances, and Resurrection of lost foundation species through introduction of resistant genotypes may represent a resounding ecological success story, but unanticipated changes to ecological processes, such as fire, should be considered.
Developing Blight-Tolerant American Chestnut Trees.
To help restore this important canopy tree, blight-tolerant American chestnut trees have been developed using an oxalate oxidase-encoding gene from wheat.
Transformation of American Chestnut (Castanea dentata (Marsh.) Borkh) Using RITA® Temporary Immersion Bioreactors and We Vitro Containers
American chestnut was successfully transformed 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.
“A reference genome assembly and adaptive trait analysis of Castanea mollissima ‘Vanuxem,’ a source of resistance to chestnut blight in restoration breeding”
The assembly of a reference genome for Chinese chestnut (C. mollissima) “Vanuxem” is presented, one of the donors of disease resistance for American chestnut restoration, and the value of the genome as a platform for research and species restoration is demonstrated.
Identifying Host Resistance to Phytophthora cinnamomi in Hybrid Progeny of Castanea dentata and Castanea mollissima
Phytophthora cinnamomi Rands, the causal pathogen of phytophthora root rot (PRR) of chestnut, is one of the main obstacles to growth of american chestnut [Castanea dentata (Marsh.) Bork.] in the


Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny.
Comparisons of Ectomycorrhizal Colonization of Transgenic American Chestnut with Those of the Wild Type, a Conventionally Bred Hybrid, and Related Fagaceae Species
Comparing ectomycorrhizal fungal colonization on a transgenic American chestnut clone expressing enhanced blight resistance to a wild-type American chestnuts, a conventionally bred American-Chinese hybrid chestnut, and other Fagaceae species shows that the oxalate oxidase gene can increase resistance against Cryphonectria parasitica without changing the colonization rate for ectomy corollary species.
Biological control of chestnut blight with hypovirulence: a critical analysis.
Overall, however, not enough is understood about the epidemiological dynamics of this system to determine the crucial factors regulating the establishment of hypovirulence in chestnut forests.
Establishment of American chestnuts (Castanea dentata) bred for blight (Cryphonectria parasitica) resistance: influence of breeding and nursery grading
Early field performance of American and Chinese chestnut and hybrid seedlings from the third backcross generation in two-aged regeneration harvests on highly productive sites in the southern Appalachians, USA showed promise for chestnut restoration, but deviations in desired growth rate was evident.
Resistance to Phytophthora cinnamomi among seedlings from backcross families of hybrid american chestnut
This work wanted to determine if any of the backcross trees selected for resistance to C. parasitica were resistant to P. cinnamomi as well because Chinese chestnut also is resistant to this pathogen.
Genetic and genomic resources for mapping resistance to Phytophthora cinnamomi in chestnut
Using combined genetic and genomic approaches, resistance to C. parasitica (Cp) has been mapped to three quantitative trait loci (QTLs) in chestnut and a marker set covering the chestnut genome has been generated for implementation in breeding for Cp resistance.
Chestnut Breeding in the United States for Disease and Insect Resistance.
The genus Castanea (family Fagaceae) is found in north temperate climates around the world, and is highly prized in many different cultures for its nutritious nuts and valuable timber. Selection for
American Chestnut [Castanea dentata (Marsh.) Borkh].
The key to successful transformation of American chestnut is having the correct combination of explant tissue, selectable and scorable markers, and a reliable regeneration system, and the more gently the somatic embryos are treated during the inoculation and co-cultivation steps, the higher the transformation efficiency.
Molecular mapping of resistance to blight in an interspecific cross in the genus castanea.
A three-generation American chestnut x Chinese chestnut pedigree was used to construct a genetic linkage map for chestnut and to investigate the control of resistance to Endothia parasitica, and multiple-marker or simultaneous models suggest that three regions have a significant effect on host response.