Summary: We propose a conceptual framework for restoration of threatened plant species that encourages integration of technological, ecological, and social spheres. A sphere encompasses ideas relevant to restoration and the people working within similar areas of influence or expertise. Increased capacity within a sphere and a higher degree of coalescing among spheres predict a greater probability of successful restoration. We illustrate this withCastanea dentata, a foundation forest tree in North America that was annihilated by an introduced pathogen; the species is a model that effectively merges biotechnology, reintroduction biology, and restoration ecology. Because ofC. dentata's ecological and social importance, scientists have aggressively pursued blight resistance through various approaches. We summarize recent advancements in tree breeding and biotechnology that have emerged fromC. dentataresearch, and describe their potential to bring new tools to bear on socio‐ecological restoration problems. Successful reintroduction ofC. dentatawill also depend upon an enhanced understanding of its ecology within contemporary forests. We identify a critical need for a deeper understanding of societal influences that may affect setting and achieving realistic restoration goals.Castanea dentatamay serve as an important model to inform reintroduction of threatened plant species in general and foundation forest trees in particular. Contents Summary 378 I. Castanea dentataas a model at the intersection of reintroduction biology and restoration ecology 379 II. Technological approaches for recovery ofCastanea dentata 381 III. Ecology of the historically dominantCastanea dentatain contemporary forests 385 IV. Societal challenges for successful reintroduction ofCastanea dentata 388 V. Conclusions 389 Acknowledgements 389 References 389

The Chinese chestnut (Castanea mollissima) carries resistance to Cryphonectria parasitica, the fungal pathogen inciting chestnut blight. The pathogen, introduced from Asia, devastated the American chestnut (Castanea dentata) throughout its native range early in the twentieth century. A highly informative genetic map of Chinese chestnut was constructed to extend genomic studies in the Fagaceae and to aid the introgression of Chinese chestnut blight resistance genes into American chestnut. Two mapping populations were established with three Chinese chestnut parents, ‘Mahogany’, ‘Nanking’, and ‘Vanuxem’, totaling 337 progeny. The transcriptome-based genetic map was created with 329 simple sequence repeat and 1,064 single nucleotide polymorphism markers all derived from expressed sequence tag sequences. Genetic maps for each parent were developed and combined to establish 12 consensus linkage groups spanning 742 cM, providing the the most comprehensive genetic map for a Fagaceae species to date. Over 75 % of the mapped markers from the Chinese chestnut consensus genetic map were placed on the physical map using overgo hybridization, providing a fully integrated genetic and physical map resource for Castanea spp. About half (57 %) of the Chinese chestnut genetic map could be assigned to regions of segmental homology with 58 % of the peach (Prunus persica) genome assembly. A three quantitative trait loci (QTL) model for blight resistance was verified using the new genetic markers and an existing interspecies (C. mollissima × C. dentata) F₂ mapping population. Two of the blight resistance QTLs in chestnut shared synteny with two QTLs for powdery mildew resistance in peach, indicating the potential conservation of disease resistance genes at these loci.

Previous loblolly pine (Pinus taeda L.) genetic linkage maps have been based on a variety of DNA polymorphisms, such as AFLPs, RAPDs, RFLPs, and ESTPs, but only a few SSRs (simple sequence repeats), also known as simple tandem repeats or microsatellites, have been mapped in P. taeda. The objective of this study was to integrate a large set of SSR markers from a variety of sources and published cDNA markers into a composite P. taeda genetic map constructed from two reference mapping pedigrees. A dense genetic map that incorporates SSR loci will benefit complete pine genome sequencing, pine population genetics studies, and pine breeding programs. Careful marker annotation using a variety of references further enhances the utility of the integrated SSR map.

Restoration of foundation species, such as the American chestnut (Castanea dentata) that was devastated by an introduced fungus, can restore ecosystem function. Understanding both the current distribution as well as biogeographic patterns is important for restoration planning. We used United States Department of Agriculture Forest Service Forest Inventory and Analysis data to quantify the current density and distribution of C. dentata. We then review the literature concerning biogeographic patterns in C. dentata. Currently, 431 ± 30.2 million stems remain. The vast majority (360 ± 22 million) are sprouts <2.5 cm dbh. Although this number is approximately 10% of the estimated pre-blight population, blight has caused a major shift in the size structure. The current-day population has a larger range, particularly west and north, likely due to human translocation. While climate change could facilitate northward expansion, limited seed reproduction makes this unlikely without assisted migration. Previous research demonstrates that the current, smaller population contains slightly higher genetic diversity than expected, although little information exists on biogeographic patterns in the genetics of adaptive traits. Our research provides a baseline characterization of the contemporary population of C. dentata, to enable monitoring stem densities and range limits to support restoration efforts.

A reference karyotype is presented for loblolly pine (Pinus taeda L., subgenus Pinus, section Pinus, subsection Australes), based on fluorescent in situ hybridization (FISH), using 18S-28S rDNA, 5S rDNA, and an Arabidopsis-type telomere repeat sequence (A-type TRS). Well separated somatic chromosomes were prepared from colchicine-treated root meristems, using an enzymatic digestion technique. Statistical analyses performed on chromosome-arm lengths, centromeric indices, and interstitial rDNA and telomeric positions were based on observations from 6 well-separated metaphase cells from each of 3 unrelated trees. Statistically, 7 of the 12 loblolly pine chromosomes could be distinguished by their relative lengths. Centromeric indices were unable to distinguish additional chromosomes. However, the position and relative strength of the rDNA and telomeric sites made it possible to uniquely identify all of the chromosomes, providing a reference karyotype for use in comparative genome analyses. A dichotomous key was developed to aid in the identification of loblolly pine chromosomes and their comparison to chromosomes of other Pinus spp. A cytomolecular map was developed using the interstitial 18S-28S rDNA and A-type TRS signals. A total of 54 bins were assigned, ranging from 3 to 5 bins per chromosome. This is the first report of a chromosome-anchored physical map for a conifer that includes a dichotomous key for accurate and consistent identification of the P. taeda chromosomes.

Chinese chestnut (Castanea mollissima) has emerged as a model species for the Fagaceae family with extensive genomic resources including a physical map, a dense genetic map and quantitative trait loci (QTLs) for chestnut blight resistance. These resources enable comparative genomics analyses relative to model plants. We assessed the degree of conservation between the chestnut genome and other well annotated and assembled plant genomic sequences, focusing on the QTL regions of most interest to the chestnut breeding community. The integrated physical and genetic map of Chinese chestnut has been improved to now include 858 shared sequence-based markers. The utility of the integrated map has also been improved through the addition of 42,970 BAC (bacterial artificial chromosome) end sequences spanning over 26 million bases of the estimated 800 Mb chestnut genome. Synteny between chestnut and ten model plant species was conducted on a macro-syntenic scale using sequences from both individual probes and BAC end sequences across the chestnut physical map. Blocks of synteny with chestnut were found in all ten reference species, with the percent of the chestnut physical map that could be aligned ranging from 10 to 39 %. The integrated genetic and physical map was utilized to identify BACs that spanned the three previously identified QTL regions conferring blight resistance. The clones were pooled and sequenced, yielding 396 sequence scaffolds covering 13.9 Mbp. Comparative genomic analysis on a microsytenic scale, using the QTL-associated genomic sequence, identified synteny from chestnut to other plant genomes ranging from 5.4 to 12.9 % of the genome sequences aligning. On both the macro- and micro-synteny levels, the peach, grape and poplar genomes were found to be the most structurally conserved with chestnut. Interestingly, these results did not strictly follow the expectation that decreased phylogenetic distance would correspond to increased levels of genome preservation, but rather suggest the additional influence of life-history traits on preservation of synteny. The regions of synteny that were detected provide an important tool for defining and cataloging genes in the QTL regions for advancing chestnut blight resistance research.