John M. McDowell


  • J. B. Stroobants Professor of Biotechnology

Pathogens have evolved sophisticated molecular weapons to exploit plants as sources of food and shelter. For example, many pathogens have evolved the capacity to export their own proteins to the interior of plant cells. Once they have gained entry to the interior of plant cells, these pathogen "effector" proteins manipulate specific plant regulatory proteins to make the plant more susceptible to infection. Plants, in turn, have evolved large collections of surveillance proteins that recognize specific pathogen molecules (including some effector proteins) as signals of invasion. This molecular recognition can trigger potent immune responses in the plant, including programmed plant cell suicide at the site of invasion.

My group investigates the molecular interplay and co-evolution between pathogens effector proteins, their targets inside plant cells, and the plant immune surveillance system. Most of our effort is focused on the interaction between the model plant Arabidopsis thaliana and the oomycete pathogen Hyaloperonospora arabidopsidis (downy mildew disease). H. arabidopsidis is a natural pathogen of Arabidopsis, and is related to downy mildew pathogens of crops as well as notorious pathogens in the Phytophthora genus (e.g., late blight of potato). We use molecular genetic and genome-enabled approaches to address the following, interrelated questions:

  1. How do pathogens manipulate plant cells? Several projects addressing to this question are underway. First, we are co-leading a coalition to sequence the H. arabidopsidis genome. This effort has provided insight into the genomic basis and evolution of "obligate biotrophy", a lifestyle in which pathogens are completely dependent on their hosts for survival. In addition, analysis of the genome has revealed a large collection of so-called "RXLR" effector proteins in H. arabidopsidis. We are currently characterizing the function of some of these genes, including their localization inside plant cells and the plant proteins that are targeted by these effectors. In addition, we are part of a coalition to develop proteins microarrays as a tool for high-throughput functional analysis of RXLR effectors. These projects will provide insight into the molecular mechanisms through which oomycete pathogens cause disease, and may reveal novel plant pathways that play a role in interaction with microbes.
  2. How do pathogens extract nutrients from their host? We are collaborating with Dr. Guillaume Pilot in a reverse genetics project to identify plant transporters that are co-opted by pathogens to supply carbon, nitrogen, and sulphur. This project will provide a clearer understanding of how pathogens utilize plants as nutritional resources, and may open the door to new strategies for engineering resistance in plants.
  3. Can fundamental research on plant-pathogen interactions be translated into new strategies for disease control? Diseases caused by plant pathogens are a perennial threat to global food security, causing 100's of billions of dollars in damage on an annual basis. We are part of a coalition to leverage oomycete pathogen genome information for control of soybean diseases, including root/stem rot caused by Phytophthora sojae. Our role in this project is to use information from pathogen genomics to search for novel resistance genes in soybean and related species. These genes can be used in molecular breeding for resistance and we expect that they will be durable against pathogen co-evolution.


Ph.D., Genetics, University of Georgia, 1995

B.S., Cellular and Molecular Biology, University of Tennessee, 1987


  • 2013 – present: Scientific Director, Fralin Life Science Institute, Virginia Tech 
  • July 2011 – present: Principal Scientist, Latham Hall, Virginia Polytechnic Institute and State University, Blacksburg
  • 2013 – present: Professor, Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg 
  • July 2006 – present: Associate Professor, Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg
  • July 2010 – December 2010: Interim Head, Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg
  • Jan. 2000 – June 2006: Assistant Professor, Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg
  • July. 1995 – December 1999: Postdoctoral Fellow in the lab of Jeff Dangl, University of North Carolina, Chapel Hill, NC

Selected Major Awards

  • Academy for Faculty Service, Virginia Tech
  • 2010 - Certificate of Teaching Excellence, College of Agriculture and Life Sciences,
  • 2007 - Henderson Award, "Outstanding Performance as a Faculty Member", Dept. of Plant Pathology, Physiology, and Weed Science, Virginia Tech,
  • 2003 - Recognized as a “Highly Cited Scientist” by the Institute for Scientific Information (ISI).  This designates a ranking among the top 10% of scientists in the field of “Plant and Animal Sciences” based on citations of published work over the previous ten years
  • 1998-2000 - USDA Postdoctoral Fellow,
  • 1995-1998 - NIH Postdoctoral Fellow,
  • 1991-1994 - NIH Predoctoral Training Grant Fellow
  • 1987 - Chancellor's Citation, "Exceptional Professional Promise", University of Tennessee
  • Honor Societies: Phi Beta Kappa, Phi Eta Sigma, Gamma Beta Phi, Gamma Sigma Delta


  • Editor in Chief, Molecular Plant-Microbe Interactions (2015-Present)
  • Senior Editor, Molecular Plant-Microbe Interactions (2010-present)
  • Editorial Board, PLOS Genetics (2012-2016)
  • Molecular Biotechnology (2008-present)
  • Review Editor, Frontiers in Plant-Microbe Interactions (2011-present)
  • Advisory Board, The Plant Journal (2004-08)
  • Editorial Board, Molecular Plant Pathology (2000-05)
  • Associate Editor, Molecular Plant-Microbe Interactions (2000-05)

Courses Taught

  • PPWS 5454 - Plant Disease Physiology and Development
  • GRAD 3104 - Translational Plant Science

Other Teaching and Advising

I am interested in the development of new training programs for Plant Science graduate students, and I contribute to the development and administration of the Translational Plant Science Ph.D. Training Program at Virginia Tech. I am the lead PI on a grant from the Virginia Tech Interdisciplinary Graduate Education Program to enhance our students' interdisciplinary training in Translational Plant Science (application of "omics" to agriculture).

My group contributes to outreach and public engagement, by participating in the Partnership for Research and Education in Plants program at Virginia Tech. This program brings together biology teachers and research scientists to guide high school students in investigating gene function in Arabidopsis. We are collaborating with high schools to learn more about how pathogen effector genes can affect various aspects of plant biology. We are also collaborating with PREP to develop new models for partnership between Translational Plant Science graduate students and high school students and teachers.

(Since 2010)

    Deb, D., Mackey, D., Opiyo, S., and McDowell, J. M., 2018, Application of alignment-free bioinformatics methods to identify an oomycete protein with structural and functional similarity to the bacterial AvrE effector protein. PLOS One, accepted.

    Deb, D., Anderson, R. G., Kim, T., Tyler, B., and McDowell, J. M., 2018, Conserved RxLR effectors from oomycetes Hyaloperonospora arabidopsidis and Phytophthora sojae suppress PAMP- and effector-triggered immunity in diverse plants, Molecular Plant-Microbe Interactions, 31:374-385.

    Dalio, R.J.D., Herlihy, J., Oliveira, T.S., McDowell, J.M., Machado, M., 2018 Effector biology in focus: a primer for computational prediction and functional characterization Molecular Plant-Microbe Interactions, 31:34-45.

    Wang, Y., Ma, W., and McDowell, J.M., 2018 Focus on Effector-Triggered Susceptibility, Molecular Plant-Microbe Interactions, 31:5.

    Michelmore, R., G. Coaker, R. Bart, G. Beattie, A. Bent, T. Bruce, D. Cameron, J. Dangl, S. Dinesh-Kumar, R. Edwards, S. Eves-van den Akker, W. Gassmann, J. T. Greenberg, L. Hanley-Bowdoin, R. J. Harrison, J. Harvey, P. He, A. Huffaker, S. Hulbert, R. Innes, J. D. G. Jones, I. Kaloshian, S. Kamoun, F. Katagiri, J. Leach, W. Ma, J.M. McDowell, J. Medford, B. Meyers, R. Nelson, R. Oliver, Y. Qi, D. Saunders, M. Shaw, C. Smart, P. Subudhi, L. Torrance, B. Tyler, B. Valent and J. Walsh 2017. Foundational and Translational Research Opportunities to Improve Plant Health. Molecular Plant Microbe Interactions, 30:515-516.

     Kong, P., McDowell, J. M., & Hong, C. (2017). Zoospore Exudates from Phytophthora nicotianae Affect Salicylic Acid Independent Defense in Arabidopsis. PLOS One,

     Anderson, R. G., Deb, D., Fedkenheuer, K., and McDowell, J. M., 2015, "Recent Progress in RXLR Effector Research", Molecular Plant-Microbe Interactions, 28:1063-1072.

    Anderson, R. G. and McDowell, J. M. (2015), A PCR assay for the quantification of growth of the oomycete pathogen Hyaloperonospora arabidopsidis in Arabidopsis thaliana. Molecular Plant Pathology. DOI: 10.1111/mpp.12247

    Kamoun S., O. Furzer, J. Jones, H. Judelson, G. Ali, R. Dalio, S. Roy, L. Schena, A. Zambounis, F. Panabières, D. Cahill, M. Ruocco, A. Figueiredo, X. Chen, J. Hulvey, R. Stam, K. Lamour, M. Gijzen, B. Tyler, N. Gruenwald, S. Mukhtar, D. Tomé, M. Tör, G. van den Ackerveken, J. M. McDowell, F. Daayf, W. Fry, H. Lindqvist-Kreuze, H. Meijer, B. Petre, J., Ristaino, K. Yoshida, P. Birch, F. Govers. (2015) The Top 10 oomycete pathogens in molecular plant pathology, Molecular Plant Pathology, DOI: 10.1111/mpp.12190.

    McDowell, J. M. (2014) Hyaloperonospora arabidopsidis: A Model Pathogen of Arabidopsis. In Genomics of Plant-Associated Fungi and Oomycetes: Dicot Pathogens (pp. 209-234). Springer Berlin Heidelberg.

    McDowell J.M., Carr J, Lorito M. (2014) Focus on translational research. Molecular Plant-Microbe Interactions. 27:195.

    Stegmann, M., Anderson, R. G., Westphal, L., Rosahl, S., McDowell, J. M., & Trujillo, M. (2014) The exocyst subunit Exo70B1 is involved in the immune response of Arabidopsis thaliana to different pathogens and cell death. Plant Signaling & Behavior, 8, e27421.

    McDowell, J.M. and Meyers, B.C., 2013, A transposable element is domesticated for service in the plant immune system, Proc. Natl. Acad. Sci. USA, 110:14821-14822

    Zhang, C., Xie, Q., Anderson, R.G., Ng, G., Seitz, N.C., Peterson, T., McClung, C.R., McDowell, J.M., Kong, D., Kwak, J., and Lu, H., 2013. Crosstalk between the Circadian Clock and Innate Immunity in Arabidopsis, PLOS Pathogens, PLOS Pathogens, Jun;9:e1003370.

    McDowell, J.M. 2013. Genomic and transcriptomic insights into lifestyle transitions of a hemi-biotrophic fungal pathogen, New Phytologist, 197:1032-1034

    Stegmann, M., Anderson, R.G., Ichimura, K., Pecenkova, T., Reuter, P., Zarsky, V., McDowell, J.M., Shirasu, K., and Trujillo, M., 2012. The Ubiquitin Ligase PUB22 Targets a Subunit of the Exocyst Complex Required for PAMP-Triggered Responses in Arabidopsis. The Plant Cell, 24:4703-4716.

    Anderson R.G., Casady, M., Fee, R., Deb, D., Vaughan, M., Fedkenheuer, K., Huffaker, A., Smeltz, E., Tyler B., McDowell, J.M., 2012. Suppression of defense responses in distantly related plants by homologous RXLR effectors from Hyaloperonospora arabidopsidis and Pytophthora sojae, The Plant Journal, 72:882-893.

    McDowell, J.M., 2011, Beleaguered Immunity. Science, 334:1354.

    McDowell, J.M., 2011, Genomes of plant rust pathogens reveal adaptations for obligate parasitism, Proc. Natl. Acad. Sci. USA, 108:8921-2.

    McDowell J.M., Hoff, T., Anderson, R., Deegan, D., 2011, Propogation, Storage, and Assays with Hyaloperonospora arabidopsidis, a model oomycete pathogen of Arabidopsis, Methods in Molecular Biology, 712:137-51.

    McDowell J.M., 2011, Examples of How New Experimental Technologies Have Enabled Landmark Advances in Understanding of Plant Immunity Over the Last Half-Century, Methods in Molecular Biology, 712:v-x.

    Plant Immunity: Methods and Protocols, 2011, Methods in Molecular Biology, Volume 712, (J. McDowell, ed.), Springer Science, New York.

    Baxter L, Tripathy S, Ishaque N, Boot N, Cabral A, Kemen E, Thines M, Ah-Fong A, Anderson R, Badejoko W, Bittner-Eddy P, Boore JL, Chibucos MC, Coates M, Dehal P, Delehaunty K, Dong S, Downton P, Dumas B, Fabro G, Fronick C, Fuerstenberg SI, Fulton L, Gaulin E, Govers F, Hughes L, Humphray S, Jiang RH, Judelson H, Kamoun S, Kyung K, Meijer H, Minx P, Morris P, Nelson J, Phuntumart V, Qutob D, Rehmany A, Rougon-Cardoso A, Ryden P, Torto-Alalibo T, Studholme D, Wang Y, Win J, Wood J, Clifton SW, Rogers J, Van den Ackerveken G, Jones JD, McDowell JM*, Beynon J, Tyler BM, 2010, Signatures of adaptation to obligate biotrophy in the Hyaloperonospora arabidopsidis genome. Science, 330:1549-51 (* Corresponding author)

    Mohr, T. J., Mammarella, N. T., Hoff, T., Woffenden, B. W., Jelesko, J. G., and McDowell, J. M., 2010, The Arabidopsis downy mildew resistance gene RPP8 is induced by pathogens and salicylic acid, and is regulated by W box cis elements. Molecular Plant-Microbe Interactions, 23:1303-15.