scholarly journals The Chinese chestnut genome: a reference for species restoration

2019 ◽  
Author(s):  
Margaret Staton ◽  
Charles Addo-Quaye ◽  
Nathaniel Cannon ◽  
Yongshuai Sun ◽  
Tetyana Zhebentyayeva ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Resistance Genes ◽  
Tree Species ◽  
Related Species ◽  
Forest Health ◽  
American Chestnut ◽  
Sources Of Resistance ◽  
Chinese Chestnut ◽  
Exotic Pests ◽  
Species Restoration

AbstractForest tree species are increasingly subject to severe mortalities from exotic pests, diseases, and invasive organisms, accelerated by climate change. Forest health issues are threatening multiple species and ecosystem sustainability globally. While sources of resistance may be available in related species, or among surviving trees, introgression of resistance genes into threatened tree species in reasonable time frames requires genome-wide breeding tools. Asian species of chestnut (Castaneaspp.) are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of a reference genome with chromosome-scale sequences for Chinese chestnut (C. mollissima), the disease-resistance donor for American chestnut restoration. We also demonstrate the value of the genome as a platform for research and species restoration, including new insights into the evolution of blight resistance in Asian chestnut species, the locations in the genome of ecologically important signatures of selection differentiating American chestnut from Chinese chestnut, the identification of candidate genes for disease resistance, and preliminary comparisons of genome organization with related species.

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.

Genome-Wide Analysis of NBS-Encoding Disease Resistance Genes in Maize Inbred Line B73

2009 ◽  
Vol 35 (3) ◽  
pp. 566-570 ◽  
Author(s):  
Jie-Ming WANG ◽  
Hai-Yang JIANG ◽  
Yang ZHAO ◽  
Yan XIANG ◽  
Su-Wen ZHU ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Inbred Line ◽  
Resistance Genes ◽  
Disease Resistance Genes ◽  
Maize Inbred Line ◽  
Genome Wide Analysis ◽  
Genome Wide

Comparative Mapping of Three Bacterial, Three Fungal, and One Virus Disease-resistance Genes in Common Bean

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 547a-547
Author(s):  
Geunhwa Jung ◽  
James Nienhuis ◽  
Dermot P. Coyne ◽  
H.M. Ariyarathne
Keyword(s):  
Disease Resistance ◽  
Common Bean ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Fungal Pathogens ◽  
Xanthomonas Campestris ◽  
Virus Disease ◽  
Disease Resistance Genes ◽  
Brown Spot ◽  
Viral Pathogen

Common bacterial blight (CBB), bacterial brown spot (BBS), and halo blight (HB), incited by the bacterial pathogens Xanthomonas campestris pv. phaseoli (Smith) Dye, Pseodomonas syringae pv. syringa, and Pseudomonas syringae pv. phaseolicola, respectively are important diseases of common bean. In addition three fungal pathogens, web blight (WB) Thanatephorus cucumeris, rust Uromyces appendiculatus, and white mold (WM) Sclerotinia sclerotiorum, are also destructive diseases attacking common bean. Bean common mosaic virus is also one of most major virus disease. Resistance genes (QTLs and major genes) to three bacterial (CBB, BBS, and HB), three fungal (WB, rust, and WM), and one viral pathogen (BCMV) were previously mapped in two common bean populations (BAC 6 × HT 7719 and Belneb RR-1 × A55). The objective of this research was to use an integrated RAPD map of the two populations to compare the positions and effect of resistance QTL in common bean. Results indicate that two chromosomal regions associated with QTL for CBB resistance mapped in both populations. The same chromosomal regions associated with QTL for disease resistance to different pathogens or same pathogens were detected in the integrated population.

scholarly journals Identification of Three Putative Signal Transduction Genes Involved in R Gene-Specified Disease Resistance in Arabidopsis

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 401-412 ◽  
Author(s):  
Randall F Warren ◽  
Peter M Merritt ◽  
Eric Holub ◽  
Roger W Innes
Keyword(s):  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Virulent Strain ◽  
Disease Resistance Genes ◽  
Avirulence Gene ◽  
Detectable Effect ◽  
Disease Resistance Gene ◽  
Protein Functions ◽  
Signal Transduction Genes

Abstract The RPS5 disease resistance gene of Arabidopsis mediates recognition of Pseudomonas syringae strains that possess the avirulence gene avrPphB. By screening for loss of RPS5-specified resistance, we identified five pbs (avrPphB susceptible) mutants that represent three different genes. Mutations in PBS1 completely blocked RPS5-mediated resistance, but had little to no effect on resistance specified by other disease resistance genes, suggesting that PBS1 facilitates recognition of the avrPphB protein. The pbs2 mutation dramatically reduced resistance mediated by the RPS5 and RPM1 resistance genes, but had no detectable effect on resistance mediated by RPS4 and had an intermediate effect on RPS2-mediated resistance. The pbs2 mutation also had varying effects on resistance mediated by seven different RPP (recognition of Peronospora parasitica) genes. These data indicate that the PBS2 protein functions in a pathway that is important only to a subset of disease-resistance genes. The pbs3 mutation partially suppressed all four P. syringae-resistance genes (RPS5, RPM1, RPS2, and RPS4), and it had weak-to-intermediate effects on the RPP genes. In addition, the pbs3 mutant allowed higher bacterial growth in response to a virulent strain of P. syringae, indicating that the PBS3 gene product functions in a pathway involved in restricting the spread of both virulent and avirulent pathogens. The pbs mutations are recessive and have been mapped to chromosomes I (pbs2) and V (pbs1 and pbs3).

Organization, Expression and Evolution of a Disease Resistance Gene Cluster in Soybean

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1961-1977
Author(s):  
Michelle A Graham ◽  
Laura Fredrick Marek ◽  
Randy C Shoemaker
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Developmental Stages ◽  
Gene Evolution ◽  
Pcr Amplification ◽  
Disease Resistance Genes ◽  
Disease Resistance Gene ◽  
R Genes ◽  
Specific Primers

Abstract PCR amplification was previously used to identify a cluster of resistance gene analogues (RGAs) on soybean linkage group J. Resistance to powdery mildew (Rmd-c), Phytophthora stem and root rot (Rps2), and an ineffective nodulation gene (Rj2) map within this cluster. BAC fingerprinting and RGA-specific primers were used to develop a contig of BAC clones spanning this region in cultivar “Williams 82” [rps2, Rmd (adult onset), rj2]. Two cDNAs with homology to the TIR/NBD/LRR family of R-genes have also been mapped to opposite ends of a BAC in the contig Gm_Isb001_091F11 (BAC 91F11). Sequence analyses of BAC 91F11 identified 16 different resistance-like gene (RLG) sequences with homology to the TIR/NBD/LRR family of disease resistance genes. Four of these RLGs represent two potentially novel classes of disease resistance genes: TIR/NBD domains fused inframe to a putative defense-related protein (NtPRp27-like) and TIR domains fused inframe to soybean calmodulin Ca2+-binding domains. RT-PCR analyses using gene-specific primers allowed us to monitor the expression of individual genes in different tissues and developmental stages. Three genes appeared to be constitutively expressed, while three were differentially expressed. Analyses of the R-genes within this BAC suggest that R-gene evolution in soybean is a complex and dynamic process.

Molecular Tags for Disease Resistance Genes in Sorghum: Improved Prospects for Mapping

2008 ◽  
pp. 247-252
Author(s):  
Clint W. Magill ◽  
Richard A. Frederiksen ◽  
Khazan Boora ◽  
Ramasamy Perumal ◽  
S. Sivaramakrishnan
Keyword(s):  
Disease Resistance ◽  
Resistance Genes ◽  
Disease Resistance Genes

scholarly journals Improving Rooting and Shoot Tip Survival of Micropropagated Transgenic American Chestnut Shoots

HortScience ◽  
2016 ◽  
Vol 51 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Allison D. Oakes ◽  
Tyler Desmarais ◽  
William A. Powell ◽  
Charles A. Maynard
Keyword(s):  
Genetic Engineering ◽  
Activated Charcoal ◽  
Shoot Tips ◽  
American Chestnut ◽  
Gelling Agent ◽  
White Oak ◽  
Oxidase Gene ◽  
Hardwood Trees ◽  
Rooting Medium ◽  
Exotic Pests

Many hardwood tree species are being threatened by exotic pests, and for some, only genetic engineering can offer a solution before functional extinction occurs. An example of how genetic engineering can be a useful tool for forest restoration is the transgenic american chestnuts, which contain a wheat oxalate oxidase gene conferring resistance to the chestnut blight. Many hundreds of these trees are needed for field trials and eventual restoration plantings throughout its natural range, but production is bottlenecked because of the difficulty of making hardwood trees produce roots through micropropagation. The presence of roots and living shoot tips precede successful acclimatization of tissue culture-produced american chestnut plantlets. In these experiments, we attempted to improve the post-rooting stage of our american chestnut propagation protocol. We examined vessel type, hormone, and activated charcoal concentrations, and using a vermiculite substrate. For plantlets with the best combination of roots and living shoot tips we recommend using semisolid post-rooting medium containing 2 g·L−1 activated charcoal and 500 mg humic acid in disposable fast-food takeout containers. When using vermiculite as a substrate, adding 2.0 g·L−1 activated charcoal to post-rooting medium without a gelling agent was the preferred treatment. Improving the survival rates of the american chestnut plantlets will benefit the american chestnut restoration project by providing more plant material for both ecological studies and eventual restoration, since pursuit of a nonregulated status for these transgenic trees will require extensive field testing. These procedures may also be applicable to other difficult-to-root hardwood trees in transgenic programs, such as american butternut, white oak, and black walnut.

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