Plant Pathology and Microbiology

Plant Pathology and Microbiology / Dr. Gwyn Beattie

Dr. Gwyn Beattie

  Dr. Gwyn Beattie
Professor; Robert Earle Buchanan Distinguished Professor of Bacteriology for Research and Nomenclature

207 Science I
Iowa State University
Ames, IA 50011
Phone: 515-294-5571

Educational Background

Ph.D. in Cell and Molecular Biology, University of Wisconsin-Madison 1991
B.A. in Chemistry, Carleton College, MN 1985

Courses Taught

Microbial Ecology and Environmental Monitoring (Micro 556)
Bacterial-Plant Interactions (Micro 477/577, Pl P 577)
Biology of Microorganisms (Micro 302)

Seminar on the Responsible Conduct of Research for Postdocs


Research Areas

Areas of emphasis:  Phytobacteriology; Microbial Ecology; Molecular Plant-Microbe Interactions; Environmental Microbiology; Bacterial Gene Expression and Functional Genomics

Research projects:  My research explores the molecular interactions of Pseudomonas syringae with plants throughout their lifecycle, including during both the epiphytic and pathogenic stages of growth, as well as phyllosphere community functions that influence plant and environmental health.  Current projects include the following:

Identifying the regulatory networks that modulate P. syringae gene expression in response to growth on and in plant leaves, with a particular focus on the hierarchy of regulons influenced by various alternative sigma factors as well as those that influence tolerance and adaptation to environmental stresses.

Characterizing the role of plant-derived quaternary ammonium compounds (QACs) (e.g., betaine, choline and carnitine) in P. syringae interactions with plants.  These compounds are important to plant and bacterial tolerance to drought and salinity stress, membrane composition, and possibly even sulfur storage and fatty acid turnover.  Our studies are characterizing the molecular components of P. syringae involved in QAC sensing, uptake, active attraction and utilization and are evaluating the role of these QAC-related activities in bacterial ecology in natural field settings.

Characterizing the role of photosensory proteins in the P. syringae lifecycle.  Light perception is common in photosynthetic bacteria but has only recently been recognized in non-photosynthetic bacteria, including P. syringaeP. syringae has multiple photosensory proteins, one that senses blue light and two that sense red/far-red light.  We are investigating the importance of light perception at the cellular, behavioral and population levels with the aim of better understanding light as a behavioral cue for phytopathogenic bacteria. 

Characterizing the role of water stress in plant responses to pathogens and the consequent importance of pathogen adaptation to water stress during growth on and in leaves.

Examining the role of rhizosphere microbial communities in enhancing the drought tolerance of plants.

Other Professional Positions and Activities


Recent Professional Positions and Activities:

Senor Editor, Molecular Plant-Microbe Interactions (2010-2015) Editorial Board, Applied and Environmental Microbiology (2003-2014)
Invited participant, American Academy of Microbiology Colloquium on "How microbes can help feed the world" 2012 (
Invited participant, American Phytopathological Society Thought Leaders, 2013
Federal program panels: NSF-Symbiosis; NSF-BREAD; USDA-Microbial Biology (2008 Panel Manager)
Session Organizer, ISME 14, Copenhagen, Denmark, 2012)

Current Institutional Positions:

Faculty Senator
College of Agriculture and Life Sciences (CALS) Caucus
CALS Peer Mentor Coordinator
Biosciences Facilities Planning Committee
Institutional Excellence Subcommittee on Graduate Education
Member, Interdepartmental Microbiology Graduate Program
Member, Interdepartmental Genetics Graduate Program
Member, Interdepartmental Molecular, Cellular and Developmental Biology Graduate Program

Freeman, B. C., C. Chen, X. Yu, L. Nielsen, K. Peterson and G. A. Beattie. 2013. Physiological and transcriptional responses to osmotic stress of two Pseudomonas syringae strains that differ in epiphytic fitness and osmotolerance. Journal of Bacteriology (in press).
Chen, C., S. Li, D.R. McKeever and G.A. Beattie. 2013. The widespread plant-colonizing bacterial species Pseudomonas syringae detects and exploits an extracellular pool of choline in hosts. The Plant Journal. 75:891-901. (cover)
Wu, L, R.S. McGrane and G.A. Beattie. 2013. Light regulation of swarming motility in Pseudomonas syringae integrates signaling pathways mediated by a bacteriophytochrome and a LOV protein. mBio 3:e00334-13. (cover)
Li, S., X. Yu, G.A. Beattie. 2013. Glycine betaine catabolism contributes to Pseudomonas syringae tolerance to hyperosmotic stress by relieving betaine-mediated suppression of compatible solute synthesis. Journal of Bacteriology 10:2415-2423.
Yu, X., S.P. Lund, R.A. Scott, J.W. Greenwald, A.H. Records, D. Nettleton, S.E. Lindow, D.C. Gross, and G.A. Beattie. 2013. Transcriptional responses of Pseudomonas syringae to growth in epiphytic versus apoplastic leaf sites. Proceedings of the National Academy of Sciences U.S.A., 110:E425-E434.
Beattie, G.A. 2011. Water relations in the interactions of foliar bacterial pathogens with plants. Annual Review of Phytopathology 49:533-555.
Malek, A.A., C. Chen, M.J. Wargo, G.A. Beattie, and D.A. Hogan. 2011. Roles of three transporters CbcXWV, BetT1 and BetT3, in Pseudomonas aeruginosa choline uptake for catabolism. Journal of Bacteriology 193:3033-3041.
Freeman, B.F., C. Chen and G.A. Beattie. 2010. Identification of the trehalose biosynthetic loci of Pseudomonas syringae and their contribution to fitnes in the phyllosphere. Environmental Microbiology 12:1486-1497.  (This paper is a Faculty of 1000 Recommended Read)
Chen, C., A. A. Malek, M. J. Wargo, D. A. Hogan and G. A. Beattie.  2010. The ATP-binding cassette transporter Cbc (cholin/betaine/carnitine) recruits multiple substrate-binding proteins with strong specificity for distinct quaternary ammonium compounds. Molecular Microbiology, 75:29-45.  (Highlighted in a MicroCommentary by Gavin Thomas in Molecular Microbiology, 75:6-9)

Freeman, B.C. and G. A. Beattie. 2009. Bacterial growth restriction during host resistance to Pseudomonas syringae is associated with leaf water loss and localized cessation of vascular activity in Arabidopsis thaliana. Molecular Plant-Microbe Interactions 22:857-867.

Sandhu, A., L. J. Halverson and G. A. Beattie. 2009. Identification and genetic characterization of phenol-degrading bacteria from leaf microbial communities. Microbial Ecology 57:276-285.

C. Chen and G. A. Beattie.  2008. Pseudomonas syringae BetT is a low affinity choline transporter that is responsible for superior osmoprotection by choline over glycine betaine.  Journal of Bacteriology 190:2717-2725.
Freeman, B. C. and G. A. Beattie. 2008. An overview of plant defenses against pathogens and herbivores. The Plant Health Instructor DOI: 10.1094/PHI-I-2008-0226-01.

C. Chen and G. A. Beattie.  2007. Characterization of the osmoprotectant transporter OpuC from Pseudomonas syringae and demonstration that cystathionine-β-synthase domains are required for its osmoregulatory function.  Journal of Bacteriology 189:6901-6912.
Sandhu, A., L. J. Halverson and G. A. Beattie. 2007. Bacterial degradation of airborne phenol in the phyllosphere. Environmental Microbiology 9:383-392 (Highlighted in Nature Reviews in Microbiology 4:880-881)
G. A. Beattie and Seibel, J. S. 2007. Uptake and localization of gaseous phenol and p-cresol in plant leaves. Chemosphere 68:528-536.
Carter, C., R. Healey, N. M. O’Tool, S. S. M. Naqvi, G. Ren, S. Park, G. A. Beattie, H. T. Horner, and R. W. Thornburg.  2007. Tobacco nectaries express a novel NADPH oxidase implicated in the defense of floral reproductive tissues against microorganisms. Plant Physiology 143: 389-399
Beattie, G. A. 2006. Plant-associated bacteria: survey, molecular phylogeny, genomics and recent advances, pp. 1-54. In S. S. Gnanamanickam (ed) Plant-Associated Bacteria. Springer, The Netherlands.

Wright, C. A. and G. A. Beattie. 2005. Bacterial species specificity in proU osmoinducibility and nptII and lacZ expression. Journal of Microbiology and Biotechnology 8:201-208.
Wright, C. A. and G. A. Beattie. 2004. Pseudomonas syringae pv. tomato cells encounter inhibitory levels of water stress during the hypersensitive response of Arabidopsis thaliana. Proceedings of the National Academy of Sciences USA 101:3269-3274
Casavant, N. C., D. Thompson, G. A. Beattie, G. J. Phillips, and L. J. Halverson. 2003. Use of a site-specific recombination-based biosensor for detecting bioavailable toluene and related compounds on roots. Environmental Microbiology. 5:238-249.
Sabaratnam, S. and G. A. Beattie. 2003. Differences between Pseudomonas syringae pv. syringae B728a and Pantoea agglomerans BRT98 in epiphytic versus endophytic colonization of leaves. Applied and Environmental Microbiology 69: 1220-1228.
Axtell, C. A. and G. A. Beattie. 2002. Construction and characterization of a proU-gfp transcriptional fusion that measures water availability in a microbial habitat. Applied and Environmental Microbiology 68:4604-4612.
Marcell, L. M. and G. A. Beattie. 2002. The effect of leaf surface waxes on leaf colonization by Pantoea agglomerans and Clavibacter michiganensis. Molecular Plant-Microbe Interactions 15:1236-1244.
Beattie, G. A. and L. M. Marcell. 2002. Effect of alterations in cuticular wax biosynthesis on the physicochemical properties and topography of maize leaf surfaces. Plant Cell and Environment 25:1-16






















































































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Department Highlights

Dr. Leonor Leandro

Assistant Professor

"What excites you about your job? I like to think that my research of fungal pathogens will have a practical application for soybean producers. I also really enjoy teaching students about fungi and the many different was these organisms are important in our lives." Read More