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College of Science | College of Agricultural Sciences

Department of Botany and Plant Pathology


Joyce E. Loper

Professor (Courtesy),
Ph.D., 1983, University of California, Berkeley
loperj@science.oregonstate.edu

Faculty of Center for Genome Research and Biocomputing

 

Office/Lab: USDA Horticultural Crops Unit
Phone: 541-738-4057

 

 

 

 

 








 

 

Research Area

Genomics and molecular genetics of prokaryotes, microbial ecology, biological control of plant disease.

Description of Research

My laboratory group studies plant-microbe interactions with an emphasis on plant-associated bacteria.  We are using molecular and ecological approaches to study the nature of microbial habitats on plant surfaces, intracellular signaling, and patterns of gene expression by bacteria living in natural environments. We recently completed the genome sequence of Pseudomonas fluorescens Pf-5, the first biological control agent for plant disease whose genomic sequence is known.   A current focus is on the identification of novel secondary metabolites from the genome of Pf-5, and evaluating these compounds for suppression of plant disease.

Research Group Members

Faculty Research Assistants/Associates

Marcella Henkels
Brenda Shaffer

Graduate Students

Sierra Hartney (PhD expected 2010)

Postdoctoral Fellow

Teresa Sweat

Visiting Scientists

Maria Carolina Quecines, University of São Paulo , Brazil (visiting graduate student)

Related Links

USDA-ARS Horticultural Crops Research Laboratory

Publications

Loper, J. E., and Gross, H. 2007. Genomic analysis of antifungal metabolite production by Pseudomonas fluorescens Pf-5.  Eur. J. Phytopathol. 119:265-278.

Péchy-Tarr, M., Bruck, D.J., Maurhofer, M., Fischer, E., Vogne, C., Henkels, M.D., Donahue, K.M., Grunder, J., Loper, J.E., Keel, C. 2008.  Molecular analysis of a novel gene cluster encoding an insect toxin in plant-associated strains of Pseudomonas fluorescens .  Environmental Microbiology PMID: 18484997

Loper, J.E., Henkels, M.D., Shaffer, B.T., Valeriote, F.A., and Gross, H. 2008.  Isolation and identification of rhizoxin analogs from Pseudomonas fluorescens Pf-5 by using a genomic mining strategy. Applied and Environmental Microbiology 74:3085-93.

Loper, J.E., Kobayashi, D.Y., and Paulsen, I.T.  2007. The genomic sequence of Pseudomonas fluorescens Pf-5: Insights into biological control.  Phytopathology 97:233-238.

Gross, H., Stockwell, V.O., Henkels, M.D., Nowak-Thompson, B., Loper, J.E., and Gerwick, W.H.  2007.  The Genomisotopic Approach: A Systematic Method to Isolate Products of Orphan Biosynthetic Gene Clusters.  Chemistry and Biology 14: 53-64.

Paulsen, I. T., Press, C. M., Ravel, J., Kobayashi, D. Y., Myers, G. S. A., Mavrodi, D. V., DeBoy, R. T., Seshadri, R., Ren, Q., Madupu, R., Dodson, R. J., Durkin, A. S., Brinkac, L. M., Daugherty, S. C., Sullivan, S. A., Rosovitz, M. J., Gwinn, M. L., Zhou, L., Schneider, D. J., Cartinhour, S. W., Nelson, W. C., Weidman, J., Watkins, K., Tran, K., Khouri, H., Pierson, E. A., Pierson, L. S., III, Thomashow, L. S. and Loper, J. E. 2005. Complete genome sequence of the plant commensal Pseudomonas fluorescens Pf-5. Nature Biotechnology 23: 873-878.  

Stockwell, V. O., and Loper, J. E. 2005. The sigma factor RpoS is required for stress tolerance and environmental fitness of Pseudomonas fluorescens Pf-5. Microbiology 151: 3001-3009.

Brodhagen, M., Paulsen, I. T., and Loper, J. E. 2005. Reciprocal regulation of pyoluteorin production with membrane transporter gene expression in Pseudomonas fluorescens Pf-5. Appl. Environ. Microbiol. 71:6900-6909.

Feil, H., Feil, W. S., Chain, P., Larimer, F., DiBartolo, G., Copeland, A., Lykidis, A., Trong, S., Nolan, M., Goltsman, E., Thiel, J., Malfatti, S., Loper, J. E., Lapidus, A., Detter, J. C., Land, M., Richardson, P. M., Kyrpides, N.C., Ivanova, N., and Lindow, S. E. 2005. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000. Proc. Natl. Acad. Sci. ( USA ) 102: 11064-11069.

Brodhagen, M., Henkels, M. D., and Loper, J. E. 2004. Positive autoregulation of the antibiotic pyoluteorin in the biological control organism Pseudomonas fluorescens Pf-5. Appl. Environ. Microbiol. 70: 1758-1766.

Anderson , L.M., Stockwell, V.O., and Loper, J.E. 2004. An extracellular protease of Pseudomonas fluorescens Pf-5 inactivates antibiotics of Pantoea agglomerans . Phytopathology 94:1228-1234.

Temple , T., Stockwell, V.O., Loper, J.E., and Johnson, K.B. 2004. Bioavailability of iron to Pseudomonas fluorescens strain A506 on flowers of Pear and Apple. Phytopathology 94:1286-1294.