Brad Day, Ph.D.

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


Dr. Brad Day received his Ph.D. from the University of Tennessee in Microbiology in 1999 where his research focus was biochemical characterization of Nod signal perception in soybean. In 2000, he received a co-sponsored National Science Foundation (U.S.) and Science and Technology Agency (Japan) postdoctoral fellowship. From 2000-2002, he conducted research at the National Institute of Agrobiological Sciences in Tsukuba, Japan, where his research contributed to the early understanding of the molecular-genetic signaling events associated with immune activation following chitin perception in rice. In 2002, he moved to U.C. Berkeley where he was a NIH Ruth L. Kirschstein Postdoctoral Fellow in the laboratory of Brian Staskawicz. As an NIH-funded postdoc at Berkeley (2002-2006), he expanded his research interests to focus on the molecular-genetic basis of host immunity, using the Arabidopsis-Pseudomonas interaction as a disease model. During this time, his research contributed to establishing what is now commonly referred to as the Guard Hypothesis. In 2006, he accepted a position at Michigan State University as an Assistant Professor. Since 2006, his lab at MSU has worked to define the role of the actin cytoskeleton as a signaling platform for immune signaling in plants, and in this area, his group was the first to identify a link between the function of the actin cytoskeleton and gene-for-gene resistance. In parallel to these studies, research in the Day lab has also published extensively in the area of immune signaling in cucumber, and more recently, has expanded into the area of DNA-nanosensor technology for the detection of pathogens. Dr. Day served as the Associate Chair for Research in the Department of Plant, Soil and Microbial Sciences. In 2017, Dr. Day was promoted to the rank of Professor.

Overview of current program:

The laboratory of Dr. Brad Day at Michigan State University focuses on the molecular-genetic and biochemical processes associated with the interaction between plants and pathogens. Specifically, we are interested in how plants protect themselves from pathogen infection using both preformed and induced defense responses. Using a combination of cell biology and genetics, we are investigating how the actin cytoskeleton impacts defense signaling in the model system Arabidopsis thaliana.

We are also using genetics and biochemistry to ask how resistance signaling is initiated during the early stages of the host-pathogen association through the function of the host actin cytoskeleton. For example, our recent work has identified a suite of Pseudomonas syringae type III effector (T3E) proteins that specifically target the Arabidopsis actin cytoskeleton. We are now working to define 1) the basal function of these specific effector targets/processes, and 2) the impact of pathogen targeting on the disruption of homeostatic cellular processes requiring actin. Our ultimate goal is to not only use pathogen T3Es as molecular and cellular probes to better define immune signaling, but to use these effectors to interrogate the function and regulation of these processes in the absence of pathogen infection.

Finally, additional recent projects in the lab aim to understand:

  1. How the downy mildew pathogen Pseudoperonospora cubensis interacts with cucumber. This work involves a combination of genomics, cell biology and chemistry to dissect the events critical to the onset of resistance in cucumber. More details about projects, people and future directions can be found on our lab website;
  2. We have developed nanosensor-based assays for DNA signatures that are rapid, sensitive, highly specific, inexpensive and adaptable to a range of disease targets. This work is being conducted in collaboration with Dr. Evangelyn Alocilja. Second, in collaboration with the laboratory of Dr. Dave Kramer, we are adapting our DNA nanosensor with PhotosynQ, to create field-deployable nanosensors to create sophisticated, portable, globally-connected phenotyping tools and analytics.
  3. As part of the newly formed MSU Plant Resilience Institute, we are working with a group of MSU scientists to uncover the molecular-genetic mechanisms that underpin plant response to pathogens and environmental stress (i.e., drought, high temperature).

Publications (last 5 years only):

  1. Zhang, B., Hua, Y., Huo, Y., Wang, J., Shimono, M., *Day, B., and *Ma, Q. (2017). TaADF4, an actin-depolymerizing factor from wheat, is required for resistance to the stripe rust pathogen Puccinia striiformis f. sp. tritici. In Press, Plant J. doi: 10.1111/tpj.13459 *co-corresponding authors.
  2. Lu, Y-J., and Day, B. (2017). Quantitative evaluation of plant actin cytoskeletal parameters during immune activation. In: Methods in Mol. Biol. Shan, L., and He, P., Eds. (In Press). DOI: 10.1007/978-1-4939-6859-6
  3. Shimono, M., Higaki, T., Kaku, H., Shibuya, N., Hasezawa, S., and Day, B. (2016). Quantitative evaluation of stomatal cytoskeletal patterns during the activation of immune signaling in Arabidopsis thaliana. PLoS One. 11: e0159291.
  4. Shimono, M., Lu, Y., Porter, K., Kvitko, B., Creason, A., Henty-Ridilla, J., He, S.Y., Chang, J.H., Staiger, C., and Day, B. (2016). The Pseudomonas syringae type III effector HopG1 induces actin filament remodeling in Arabidopsis in association with disease symptom development. Plant Physiol. 171: 2239-2255.
  5. Burkhardt, A. and Day, B. (2016). Plant pathogenic oomycetes: Counterbalancing resistance, susceptibility, and adaptation. Can. J. Plant Pathol. 38: DOI: 10.1080/07060661.2016.1149519
  6. Burkhardt, A. and Day, B. (2016). Transcriptome and small RNAome dynamics during a resistant and susceptible interaction between cucumber and downy mildew. Plant Genome. doi: 10.3835/plantgenome2015.08.0069
  7. Tanabe, S., Onodera, H., Hara, N., Ishii-Minami, N., Day, B., Fujisawa, Y., Hagio, T., Toki, S., Shibuya, N., Nishizawa, Y., and Minami, E. (2015). The elicitor-responsive gene for a GRAS family protein, CIGR2, suppresses cell death in rice inoculated with rice blast fungus via activation of a heat shock transcription factor, OsHsf23. Biosci. Biotech. Biochem. 80: 145-151.
  8. Burkhardt, A., Buchanan, A., Cumbie, J.S., Savory, E.A., Chang, J.H.*, and Day, B.* (2015). Alternative splicing in the obligate biotrophic oomycete pathogen, Pseudoperonospora cubensis. Mol. Plant-Microbe Interact. 28: 298-309. *co-corresponding authors.
  9. Corrion, A., and Day, B. (2015). Pathogen resistance signaling in plants. In: eLS. John Wiley & Sons, Ltd: Chichester. DOI: 10.1002/9780470015902.a0020119.pub2.  pp. 1-14.
  10. Porter, K., and Day, B. (2015). From filaments to function: The role of the plant actin cytoskeleton in pathogen perception, signaling and immunity. J. Int. Plant. Biol. 58: 299-311.
  11. Li, J., Henty-Ridilla, J.L., Staiger, B.H., Day, B., and Staiger, C.J. (2015). Capping protein integrates multiple MAMP signaling pathways to modulate actin dynamics during plant innate immunity. Nature Comm. 28: 7206. doi: 10.1038/ncomms8206.
  12. Henty-Ridilla, J.L., Li, J., Day, B., and Staiger, C.J. (2014). ADF4 regulates actin dynamics during innate immune signaling. Plant Cell. 26: 340-352
  13. Burkhardt, A., and Day, B. (2013). A genomics perspective on cucurbit-oomycete interactions. Plant Biotech. 30: 265-271.
  14. 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: e1003290. doi:10.1371/journal.ppat.1003290. *co-corresponding authors.
  15. 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.
  16. 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: e1003006. doi:10.1371/journal.ppat.1003006
  17. 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.
  18. 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.
  19. 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.
  20. 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.
  21. 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.
  22. 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.
  23. Day, B., Henty, J., Porter, K., and Staiger, C. (2011). The pathogen-actin connection: A platform for defense signaling in plants. Ann. Rev. Phytopathol. 49: 483-506.
  24. 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.
  25. 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.
  26. 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.
  27. 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.