Barbara Kunkel

Barbara Kunkel

​Professor of Biology
Associate Chair of Undergraduate Education
PhD, Harvard University

contact info:

mailing address:

  • Washington University
    CB 1137
    One Brookings Drive
    St. Louis, MO 63130-4899

Professor Kunkel's research group is interested in the signaling and regulatory events that govern interactions between bacterial plant pathogens and their hosts.

Kunkel's group is studying the bacterial plant pathogen Pseudomonas syringae and one of its hosts, Arabidopsis thaliana, a system in which both pathogen and host are amenable to genetic and molecular analysis. The group's approach involves identifying and characterizing both pathogen and plant genes that govern whether interactions between these two organisms result in disease or not. The research currently focuses on two central areas: 1) The molecular basis of pathogenicity in P. syringae, and 2) The physiological processes and signaling pathways in the plant host that are modified by pathogen virulence factors.


Photo caption: Expression of the Pseudomonas syringae virulence factor avrRpt2 in plant cells promotes pathogen virulence. Disease symptoms caused by P. syringae on transgenic plants expressing the bacterial gene avrRpt2 (right) are much more severe than those on non-transgenic control plants (left).

recent courses

How Plants Work: Physiology, Growth, and Metabolism

Bio 4023: This course introduces students to the fundamentals of how plants grow, metabolize and respond to their environment. Topics to be covered include the conversion of light energy into chemical energy through photosynthesis and carbon fixation, nitrogen assimilation, water and mineral uptake and transport, source-sink relationships and long-distance transport of carbon and nitrogen, cell growth and expansion, hormone physiology and physiological responses to a changing environment. Prerequisite: Bio 2970, or permission of instructors.

    Special Topics in Biology: Plant-Microbe Interactions

    Bio 1771/1772: Course Description: This is a research-based laboratory course offered by Dr. Barbara Kunkel in the Biology Department. The small class size and laboratory setting of the course is intended to foster development of student-professor mentoring relationships.

      Principles of Biology I

      Bio 2960: The course provides an introduction to cell biology, biochemistry, and molecular biology. An understanding of cellular structure and mechanisms, and the properties of biological macromolecules are integrated with a discussion of the flow of genetic information within cells. Examples of how these concepts can be applied to selected areas in modern biology will be discussed. Weekly labs reinforce material from lectures and explore common laboratory techniques and computer-based resources.

        Selected Publications

        Chung, K. M., Demianski, A. J., Harrison, G. J., Laurie-Berry, N., Mitsuda, N., Kunkel, B. N.  2022. Jasmonate Hypersensitive 3 (JAH3) negatively regulates both jasmonate and ethylene-mediated responses in Arabidopsis. J. Exp. Bot. In Press. erac208,

        Djami-Tchatchou, A. T., Li, A., Li, Stodghill, P., Filiatrault, M. J. and Kunkel, B. N. Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000. 2022. J. Bacteriol. 204. e00380-21

        B. N. Kunkel and J. Johnson.  2021. Auxin plays multiple roles during plant-pathogen interactions. Cold Spring Harbor Perspectives: Auxin Signaling. Editors: Dolf Weijers, Karin Ljung, Mark Estelle, and Ottoline Leyser.Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a040022.

        Djami-Tchatchou, A.  Harrison, G., Harper, C., Wang,R., Prigge, M. J.,  Estelle, M. and Kunkel, B. N. 2020. Dual role of auxin in regulating plant defense and bacterial virulence gene expression during Pseudomonas syringae PtoDC3000 pathogenesis. Molec. Plant-Microbe Interact. 33: 1059–1071.

        Kunkel, B. N. and Harper, C. P. 2018. The roles of auxin during interactions between bacterial plant pathogens and their hosts. J. Exp. Bot. 69:245-254.

        McClerklin, S. A., Lee, S. G., Harper, C. P., Nwumeh, R., Jez, J.M. and Kunkel, B.N. 2018. Indole-3-acetaldehyde dehydrogenase-dependent auxin synthesis contributes to virulence of Pseudomonas syringae strain DC3000. PLoS Pathog. 2018 Jan 2;14(1):e1006811. doi: 10.1371/journal.ppat.1006811. (Abstract/PDF)

        Cui, F., Wu, S., Sun, W., Coaker, G., Kunkel, B. N., He, P.  and Shan, L. 2013. Pseudomonas syringae type III effector AvrRpt2 promotes pathogen virulence via stimulating Arabidopsis Aux/IAA protein turnover. Plant Physiol. 162: 1018–1029 (Abstract/PDF)

        Mutka, A. M., Fawley, S., Tsao, T., and B. N. Kunkel. 2013. Auxin promotes susceptibility to Pseudomonas syringae via a mechanism independent of suppression of salicylic acid-mediated defenses. Plant J. 74: 746–754 (Abstract/PDF)

        Melotto, M. and B. N. Kunkel, 2013. Virulence strategies of plant pathogenic bacteria. In: The Prokaryotes, 4th Ed. Rosenberg E, Stackebrand E, DeLong EF, Thompson F, Lory S (eds). Springer-Verlag, Berlin. (Abstract/PDF)

        Demianski. A. J., Chung, K. Mi, and B. N. Kunkel. 2012.  Analysis of JAZ gene expression during Pseudomonas syringae pathogenesis reveals that JIN1/AtMYC2 regulates only a subset of JAZ genes and that JAZ10 is a negative regulator of disease symptom development. Mol Plant Pathol. 13: 46–57. (Abstract/PDF)

        Mellgren, E. M., Kloek, Andrew P. and B. N. Kunkel, 2009. Mqo, a tricarboxylic acid cycle enzyme, is required for virulence of Pseudomonas syringae pv. tomato strain DC3000 on Arabidopsis thaliana. J. Bacteriol. 191:3132-3141. (Abstract/PDF)

        Chen, Z., Agnew, J. L., Cohen, J. D., He, P., Shan, L.,Sheen, J. and B. N. Kunkel. 2007. Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis thaliana auxin physiology. Proc. Nat. Acad. Sci. USA. 104: 20131-20136. (Abstract/PDF)

        Laurie-Berry, N., Joardar, V., Street, I. H., and B. N. Kunkel. (2006) The Arabidopsis thaliana JASMONATE INSENSITIVE 1 gene is required for suppression of salicylic acid-dependent defenses during infection by Pseudomonas syringae. Molec. Plant-Microbe Interact. 19: 789-800.

        Brooks, D. M., Bender, C. L., and B. N. Kunkel. (2005) The Pseudomonas syringae phytotoxin coronatine promotes virulence by overcoming salicylic acid-dependent defences in Arabidopsis thaliana. Mol. Plant Pathol 6: 629-639. (Abstract/PDF)

        Lim, M. T. S. and B. N. Kunkel. (2005) The Pseudomonas syringae gene avrRpt2 contributes to the virulence on tomato.Molec. Plant-Microbe Interact 18:626-633.

        Preiter, K., Brooks, D. M., Penaloza-Vazquez, A., Sreedharan, A., Bender, C. L., and B. N. Kunkel. (2005) . Novel virulence gene of Pseudomonas syringae pathovar tomato strain DC3000. J. Bacteriol. 187: 7805-14. (Abstract/PDF)

        Z. Chen, A. P. Kloek, A. Cuzick, D. Tang, W. Moeder, D. Klessig, J. McDowell, R. Innes, and B. N. Kunkel (2004) The Pseudomonas syringae AvrRpt2 protein functions downstream or independently of salicylic acid to promote virulence on Arabidopsis thaliana. Plant J. 37:494-504. (Abstract/PDF)

        Brooks, D. M, G. Hernandez-Guzman, A. P. Kloek, F. Alarcn-Chaidez, A. Sreedharan, V. Rangaswamy, A. Pealoza-Vazquez, C. L. Bender and B. N. Kunkel. (2004) .Identification and characterization of a well-defined series coronatine biosynthetic mutants of Pseudomonas syringae pv. tomato DC3000. Molec. Plant-Microbe Interact. 17:162-274.

        Lim, M. T. S., and B. N. Kunkel (2004) The Pseudomonas syringae type III effector AvrRpt2 promotes virulence independently of RIN4, a predicted virulence target in Arabidopsis thaliana. Plant J. 40:790-798. (Abstract/PDF)

        Boch, J., V. Joardar, L. Gao, T. L. Robertson, M. Lim, and B. N. Kunkel (2002). Identification of Pseudomonas syringae genes induced during infection of Arabidopsis thaliana. Mol. Microbiol. 44: 73-88.

        Kloek, A. P., M. L. Verbsky, S. B. Sharma, J. E. Schoelz, J. Vogel, D. F. Klessig, and B. N. Kunkel (2001).  Resistance to Pseudomonas syringae conferred by an Arabidopsis thaliana coronatine insensitive (coi1) mutation occurs through two distinct mechanisms.  Plant J. 26:509-522.

        Chen, Z., A. P. Kloek, J. Boch, F. Katagiri and B. N. Kunkel (2000).  The Pseudomonas syringae avrRpt2 gene product promotes pathogen virulence from inside plant cells.  Molec. Plant-Microbe Interact. 13:1312-1321.