Brad Day

Associate Professor and Associate Department Chair for Research - Molecular biology of host-pathogen interaction

Brad Day


Molecular Plant Science Building
1066 Bogue Street Rm 4200
East Lansing, MI 48824-6254

Phone: 517-353-7991

Day Lab Website

Click here to see a list of Brad Day's publications on Google Scholar.


B.S., The University of Tennessee, Microbiology
Ph.D., The University of Tennessee, Microbiology

General areas of expertise:

Molecular Biology of Host-Pathogen Interactions


Overview of current program:

Research in my laboratory focuses on the molecular-genetics of innate immunity in plants. Using a combination of molecular biology and biochemical approaches, we are interested in understanding the signaling mechanisms which lead to the activation of host defense responses following pathogen perception. Understanding host specificity, as well as the specificity which regulates the activation of these responses is key to understanding plant disease resistance. We are currently using the model interaction, Arabidopsis thaliana-Pseudomonas syringae, to address questions related to 1) the involvement of the actin cytoskeleton, and its association with gene-for-gene resistance responses, 2) the characterization of a novel GPI-anchored protein required for defense signaling, and 3) the identification of conserved signaling mechanisms which contribute to the activation of defenses in a broad range of plant-pathogen interactions. For the latter, we are currently conducting several mutagenesis screens to identify genetic loci which contribute to resistance in Arabidopsis not to only P. syringae, but also Colletotrichum spp., one of the most important and common fungal genus causing anthracnose or more than 50 host plant species.



Burkhardt, A., and Day, B. (2013). A genomics perspective on cucurbit-oomycete interactions. Plant Biotech. in press.

Henty, J.L., Shimono, M., Li, J., Chang, J.H., Day, B.*, and Staiger, C.J.* (2013). The plant actin cytoskeleton is a novel component of innate immunity. PLoS Path. 9(4): e1003290. doi:10.1371/journal.ppat.1003290. *corresponding authors.

Vogt, I., Wohner, T., Richter, K., Wensing, A., Geider, K., Sundin, G., Savory, E.A., Day, B., Hanke, M-V., Flachowsky, H., and Peil, A. (2013). Gene-for-gene relationship in the host-pathogen-system Malus x robusta 5 – Erwinia amylovora. New Phytol. 197: 1262-1275.

Porter, K., Shimono, M., Tian, M., and Day, B. (2012). Arabidopsis Actin-depolymerizing Factor-4 links pathogen perception, defense activation and transcription to cytoskeletal dynamics. PLoS Pathogens, 8(11): e1003006. doi:10.1371/journal.ppat.1003006

Savory, E.A., Adhikari, B., Vaillancourt, B., Hamilton, J., Buell, C.R., and Day, B. (2012). RNA-seq analysis of the Pseudoperonospora cubensis transcriptome during infection of cucumber (Cucumis sativus). PloS ONE. 10.1371/journal.pone.0035796.

Adhikari, B., Savory, E.A., Vaillancourt, B., Hamilton, J., Day, B. and Buell, C.R. (2012). Transcriptomic response of Cucumis sativus to Pseudoperonospora cubensis infection. PLoS One. 0.1371/journal.pone.0034954.

Savory, E.A., Zou, C., Adhikari, B., Hamilton, J., Buell, C.R., Shiu, S-H., and Day, B. (2012). Alternative splicing of a Pseudoperonospora cubensis multi-drug transporter generates a translocated RXLR effector protein that elicits a rapid cell death in cucumber. PLoS ONE. 10.1371/journal.pone.0034701.

Runge, F., Telle, S., Ploch, S., Savory, E., Day, B., Sharma, R., and Thines, M. (2011). Phylogenetic relationships of downy mildews and their relatives reveal a high degree of paraphyly in Phytophthora. IMA Fungus. 2: 163-171.

Henty, J.L., Bledsoe, S.W., Khurana, P., Meagher, R.B., Day, B., Blanchoin, L., and Staiger, C.J. (2011). ADF4 modulates the stochastic dynamic behavior of actin filaments in the cortical array of plant cells. Plant Cell. 23: 3711-3726.

Varbanova, M., Porter, K., Lu, F., Ralph, J., Hammerschmidt, R., Jones, A.D., and Day, B. (2011). Molecular and biochemical basis for stress induced accumulation of free and bound p-coumaraldehyde in Cucumis sativus. Plant Physiol. 157: 1056-1066.

Day, B., Henty, J., Porter, K., and Staiger, C. (2011). The pathogen-actin connection: A platform for defense signaling in plants. Annu. Rev. Phytopathol. 49: 483-506.

Miles, T.D., Day, B., and Schilder, A. (2011). Identification of differentially expressed genes in a resistant versus a susceptible blueberry cultivar after infection by Colletotrichum acutatum. Mol. Plant Pathol. 12: 473-477.

Knepper, C., Savory, E., and Day, B. (2011). Arabidopsis NDR1 is an integrin-like protein with a role in nutrient stasis and plasma membrane-cell wall adhesion. Plant Physiol. 156: 286-300.

Tian, M., Win, J., Savory, E., Burkhardt, A., Held, M., Brandizzi, F., and Day, B. (2011). 454 genome sequencing of Pseudoperonospora cubensis reveals effector proteins with a putative QXLR translocation motif. Mol. Plant-Microbe Interact. 24: 543-553.

Savory, E.A., Granke, L.L., Quesada-Ocampo, L.M., Varbanova, M., Hausbeck, M.K., and Day, B. (2011). The cucurbit downy mildew pathogen Pseudoperonospora cubensis. Mol. Plant Pathol. 12: 217-226.

Knepper, C. and Day, B. (2010). From perception to activation: The molecular-genetic and biochemical landscape of resistance signaling in plants. The Arabidopsis Book. May 14, 2010; 10.1199/tab.0124.

Chinnapun, D., Tian, M., Day, B., and Churngchow, N. (2010). Inhibition of a Hevea brasiliensis protease by a Kazal-like serine protease inhibitor from Phytophthora palmivora. Physiol. Mol. Plant Path. 74: 27-33.

Tian, M., Chaudhry, F., Ruzicka, D.R., Meagher, R.B., Staiger, C.J., and Day, B. (2009). Arabidopsis actin depolymerizing factor AtADF4 mediates defense signal transduction triggered by the Pseudomonas syringae effector AvrPphB. Plant Physiol. 150: 815-824.

Day, B., Dahlbeck, D., and Staskawicz, B.J. (2006). The RIN4-NDR1 interaction mediates the differential activation of at least three members of the CC-NB-LRR class of resistance proteins in Arabidopsis thaliana. Plant Cell. 18: 1-10.

Chisholm, S*., Coaker, G*., Day, B*., and Staskawicz, B.J. (2006). Host-microbe interactions: shaping the evolution of the plant immune response. Cell. 124: 1-12. *Co-First Authors.

Day, B., Dahlbeck, D., Huang, J., Chisholm, S.T., Li, D., and Staskawicz, B.J. (2005). Molecular basis for the RIN4 negative regulation of RPS2 disease resistance. Plant Cell. 17: 1292–1305.

Chisholm ST, Dahlbeck D, Krishnamurthy N, Day B, Sjolander K, Staskawicz BJ. (2005). Molecular characterization of proteolytic cleavage sites of the Pseudomonas syringae effector AvrRpt2. Proc. Natl. Acad. Sci. USA. 102: 2087-2092.

Leister, R.T., Dahlbeck, D., Day, B., Li, Y., Chesnokova, O., and Staskawicz, B.J. (2005). Molecular genetic evidence for the role of NbSGT1 in the intra-molecular complementation of Bs2 protein activity in Nicotiana benthamiana. Plant Cell. 17: 1268-1278.

Coppinger, J.P, Repetti, P., Day, B., Dahlbeck, D., Mehlert, A., and Staskawicz, B. (2004). Overexpression of the plasma membrane-localized NDR1 protein results in enhanced bacterial disease resistance in Arabidopsis thaliana. Plant J. 40: 225-237.



Courses taught:

PLP 881, Biochemical and Molecular Plant Pathology