|The American chestnut tree, Castanea
dentata, was once one of the most important and abundant trees
in the eastern United States. Just before 1900, a pathogen, Cryphonectria
parasitica, (formally Endothia parasitica) was introduced
into the U.S. and within about 50 years reduced the American chestnut
from its predominant role in the forest as a keystone species,
to now an understory shrub struggling to survive. The reason American
chestnuts still survive today is due to there ability to resprout
from their root collar. Unfortunately, the chestnut blight usually
kills the tree back to the ground before it matures. The American
chestnut research and restoration project is a collaborative effort
to produce blight-resistant American chestnut through the use
of genetic engineering. Our lab is focused on the identification
and cloning of genes and promoters that can be used to enhance
blight resistance in American chestnut trees. Our first transgenic
somatic embryo cultures were produced in the spring of 2004 (the
one hundred year anniversery of the discovery of the chestnut
blight in 1904). Shoots have been regenerated from these cultures
in the fall of 2004. Whole potted plants are expected in 2005 and field trials are scheduled to begin the following spring in 2006.
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American Elm Project
The American elm tree is another heritage tree that once graced the streets of many U.S. towns. For example, in 1950 Syracuse, New York had about 53,000 elms along its streets, but today it is difficult to find any survivors due to the introduced Dutch elm disease. In an effort to restore this tree, we have developed tissue culture and transformation techniques. Field trials of the first transgenic American elms expressing ESF antimicrobial peptides in their vascular tissues have begun in 2005.
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Hybrid poplar is an important woody biomass and potential bioenergy
tree species. Utilization of these trees are limited in the eastern
United States due to a fungal pathogen, Septoria musiva. We have
made several gene constructs encoding gene products to enhance poplar¼s
resistance to Septoria canker and leaf spot and also other fungal pathogens.
Some of the genes we are currently testing singularly and in combinations
are: synthetic antimicrobial peptides (ESF peptides), oxalate oxidase
from wheat, and a chitinase from Trichoderma, and cystatin (a proteinase
inhibitor) from American chestnut. We are also testing the use of TMV¼s
NIa protease to deliver multiple gene products from a single gene construct.
We have produced several transgenic hybrid poplar which we have tested
in vitro and are currently testing in the field.
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Sisco, P.H., Sederoff, R.R., Tomkins, J.P., Carlson, J.E., Kubisiak, T.L., Staton, M.E., Hebard, F.V., Anagnostakis, S.L., Powell, W.A. and Smith, C.P. 2009. The United States National Science Foundation project on developing tools for the study of the Fagaceae: Castanea, Quercus, and Fagus. Acta Hort. (ISHS) 844:267-274
Barakat, A., D. S. DiLoreto, Y. Zhang, C. Smith, K. Baier, W. A. Powell, N. Wheeler, R. Sederoff, J. E. Carlson. 2009. Comparison of the transcriptomes of American chestnut (Castanea dentata) and Chinese chestnut (Castanea mollissima) in response to the chestnut blight infection. BMC Plant Biology. 9:51 (pp. 1-11)
Andrew E. Newhouse, Nicholas S. Kaczmar, Charles A. Maynard. American Elm, in Kole, C. and Hall, T. C. (eds.), “Compendium of Transgenic Crop Plants: Transgenic Forest Tree Species”, Blackwell Publishing, Oxford, UK, 2008, pp 241-262
Maynard, C.A., W.A. Powell, L.D. Polin-McGuigan, A.M. Viéitez, A. Ballester, E. Corredoira, S.A. Merkle and G.M. Andrade (2008) Chestnut. In: Kole, C., Hall, T.C. (eds.) “A Compendium of Transgenic Crop Plants: Forest Tree Species”, Blackwell Publishing, Oxford, UK, 2008.
Newhouse, A.E., F. Schrodt, H. Liang, C.A. Maynard, W.A. Powell. 2007. Transgenic American Elm Shows Reduced Dutch Elm Disease Symptoms and Normal Mycorrhizal Colonization. Plant Cell Reports 26:977-987
Welch, A.J., C.A. Maynard, A.J. Stipanovic, and W.A. Powell. 2007. The effects of oxalic acid on transgenic Castanea dentata callus tissue expressing oxalate oxidase. Plant Science 172:488-496
Powell, W. A., P. Morley, M. King and C. A. Maynard. 2007. Small stem chestnut blight resistance assay. Journal of The American Chestnut Foundation 21(2): 34-38
Rothrock, R., L. McGuigan, A. Newhouse, W.A. Powell and C.A. Maynard. 2007. Plate Flooding as an Alternative Agrobacterium-Mediated Transformation Method for American Chestnut Somatic Embryos. Plant Cell Tissue and Organ Culture 88:93-99
Merkle, S.A., G.M. Andrade, C.J. Nairn, W.A. Powell and C.A. Maynard. 2007. Restoration of threatened species: a noble cause for transgenic trees. Tree Genetics and Genomes 3:111-11
Polin L.D., H. Liang, R. Rothrock, M. Nishii, D. Diehl, A. Newhouse, C.J. Nairn, W. A. Powell, and C.A. Maynard. 2006. Agrobacterium-mediated transformation of American chestnut (Castanea dentata (Marsh.) Borkh.) somatic embryos. Plant Cell Tissue and Organ Culture. 84: 69-79
Powell, W.A., C.A. Maynard, B. Boyle, and A. Seguin. (2006). Fungal and bacterial resistance in transgenic trees. Pages 235-252. In: M. Fladung and D. Ewald, Eds., Tree Transgenics, Recent Developments. Springer, Berlin Heidelberg, Germany. 357p.
Newhouse, A., F. Schrodt, C. Maynard, and W. Powell. (2006). American elm (Ulmus americana). Pages 99-112 In: K. Wang, Ed., Agrobacterium Protocols: (2nd edition) Methods in Molecular Biology Book Series #344, Humana Press, Inc., Totowa, NJ. 485 pages
Maynard, C.A., L. D. Polin, S. LaPierre, R. E. Rothrock, and W. A. Powell. (2006). American chestnut (Castanea dentata (Marsh.) Borkh.). pages 239-251. In: K. Wang, Ed., Agrobacterium Protocols: (2nd edition) Methods in Molecular Biology Book Series #344, Humana Press, Inc., Totowa, NJ.
Liang, H., H. Gao, C.A. Maynard, and W.A. Powell. 2005. Expression of a self-processing, putative pathogen resistance-enhancing gene construct in Arabidopsis. Biotech. L. 27:435-442
- Connors, B.J., M. Miller, C.A. Maynard, and W.A. Powell. 2002. Cloning and characterization of promoters from American chestnut capable of directing reporter gene expression in transgenic Arabidopsis plants. Plant
- Connors, B.J., N.P. Laun, C.A. Maynard, and W.A. Powell. 2002. Molecular
characterization of a gene encoding a cystatin expressed in the stems
of American chestnut (Castanea dentata).
- Liang, H. C.M. Catranis, C.A. Maynard, and W.A. Powell. 2002. Enhanced
resistance to the poplar pathogen, Septoria musiva, in hybrid poplar
transformed with genes encoding antimicrobial peptides. Biotechnol.
- Connors, B.J., C.A. Maynard, and W.A. Powell. 2001. Expression sequence
tags from stem tissue of American chestnut. Biotechnol.
- Liang, H., C.A. Maynard, R.D. Allen, W.A. Powell. 2001. Increased
Septoria musiva resistance in transgenic hybrid poplar leaves expressing
a wheat oxalate oxidase gene. Plant
Mol. Biol. 45:619-629
- Powell, W.A., C.M. Catranis, and C.A. Maynard. 2000. Design of self-processing
antimicrobial peptides plant protection. Letters
in Applied Microbiology 31:163-168
- Xing, Z.Z., W.A. Powell, and C.A. Maynard. 1999. Development and germination
of somatic embryos in American chestnut. Plant
Cell Tissue and Organ Culture 57:47-55
- Maynard, C., Z. Xing, S. Bickel, and W. Powell. 1999. Using Genetic
Engineering to Help Save the American Chestnut: A Progress Report. Journal
of the American Chestnut Foundation, 12 (2):41-56.
- Powell, W.A. and C.A. Maynard. 1997. Designing small antimicrobial
peptides and their encoding genes. pp.165-172. In Micropropagation,
Genetic Engineering, and Molecular Biology of Populus , N.B. Klopfenstein,
Y.W. Chun, M.-S. Kim, M.R. Ahuja, eds. M.C. Dillon, R.C. Carman, L.G.
Eskew, tech. eds. Tech. Rep. RM-GTR-297. Fort Collins, CO: U.S. Department
of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment
- Xing, Z., M.F. Satchwell, W.A. Powell, and C.A. Maynard. 1997. Micropropagation
of American chestnut: Increasing rooting rate and preventing shoot-tip
necrosis. In Vitro Cellular and Developmental Biology-Plant 33:43-48
- Kistler, H.C., U. Benny, and W.A. Powell. 1997. Linear mitochondrial
plasmids of Fusarium oxysporum contain genes with sequence similarity
to a reverse transcriptase from Neurospora spp. Applied and Environmental
- Powell, W.A., C.M. Catranis, and C.A. Maynard. 1995. Synthetic Antimicrobial
Peptide Design. Molecular Plant-Microbe Interactions 8:792-794
- Powell, W.A. 1995. Vegetative incompatibility and mycelial death of
Cryphonectria parasitica monitored with pH indicators. Mycologia 87:738-741
- Powell, W.A. and Z.H. Yan. 1995. Recombination between Fusarium oxysporum
telomeres and pUC ampicillin resistance gene in a transforming vector.
Fungal Genetics Newsletter 42:62-64
- Rizwana, R. and W.A. Powell. 1995. Ultraviolet light-induced heterokaryon
formation and parasexuality in Cryphonectria parasitica. Experimental
- Rizwana, R. and W.A. Powell. 1992. Ultraviolet light-induced instability
of vegetative compatibility groups of Cryphonectria parasitica. Phytopathology
- Milgroom, M.G., S.E. Lipari, and W.A. Powell. 1992. DNA fingerprinting
and analysis of population structure in the chestnut blight fungus,
Cryphonectria parasitica. Genetics 131:297-306
- Powell, W.A. and H.C. Kistler. 1990. In vivo rearrangement of foreign
DNA by Fusarium oxysporum produces linear self-replicating plasmids.
J. Bact. 172:3163-3171
- Gobbi, E., Y. Wang, R.M. Martin, W.A. Powell, and N.K. Van Alfen.
1990. Mitochondrial DNA of Cryphonectria parasitica: lack of migration
between vegetatively compatible strains. Molecular Plant-Microbe Interactions
- Powell, W.A. and N.K. Van Alfen. 1987. Differential accumulation of
poly(A)+ RNA between virulent and dsRNA-induced hypovirulent strains
of Cryphonectria (Endothia) parasitica. Mol. Cell. Biol. 7:3688-3693
- Powell, W.A. and N.K. Van Alfen. 1987. Two non-homologous viruses
of Cryphonectria (Endothia)parasitica reduced the accumulation of specific
virulence associated polypeptides. J. Bact. 169:5324-5326
- Hansen, D.R., N.K. Van Alfen, K. Gillis, and W.A. Powell. 1985. Naked
dsRNA associated withhypovirulence of Endothia parasitica is packaged
in fungal vesicles. J. Gen. Virol. 66:2605-2614
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Title: Antimicrobial Peptides
Covers genes encoding antimicrobial peptides designed for
enhancing pathogen resistance in plants.
U.S. Patent No. 5,856,127
Date of Patent: 1/5/99
Abstract: The present invention is directed to antimicrobial
polypeptides and to nucleic acid molecules encoding the antimicrobial
polypeptides. The polypeptide consists of 15 to 20 amino acids and has
an amphipathic alpha helix structure, wherein 3 or more of the amino acids
form a positively charged domain extending axially along the alpha helix.
Expression vectors, host cells, and transgenic plants, as well as methods
of producing plants having improved resistance to fungal and bacterial
infestation, are also proved.
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