Kevin L. Hockett, Ph.D.

Kevin L. Hockett, Ph.D.

  • Assistant Professor of Microbial Ecology
  • Lloyd Huck Early Career Professor
316 Buckhout Lab (office)
315 Buckhout Lab (lab)

University Park, PA 16802

Areas of Expertise

  • Bacteriology
  • Phyllosphere Microbiology
  • Protein-mediated Bacterial Antagonism
  • Molecular Biology



  • B.S., Microbiology, Oregon State University, Corvallis, OR
  • Ph.D., Microbiology, University of California, Berkeley, Berkeley, CA


My lab's research focuses on understanding how organismal and molecular interactions affect the ecology and evolution of plant-associated bacteria. I utilize Pseudomonas syringae as a model system, which allows me to draw on the wealth of genetic, genomic, and phenotypic resources available for this phytopathogen. Specifically, I am interested a diverse group of protein-based toxins (termed bacteriocins) produced by P. syringae. Any given bacteriocin exhibits an extremely narrow spectrum of killing, however, a strain may produce several versions or classes of bacteriocins. I use a combination of molecular-genetic, phylogenetic, genomic, and bioinformatic approaches to test hypotheses related to these interactions.

Specific questions include:

  • What are the mechanisms by which sensitive strains become resistant to a given bacteriocin? How does acquiring resistance affect the fitness of a strain, such as when interacting with its host plant?
  • Why does a given strain produce several different bacteriocins? How does a strain's bacteriocin diversity arise?
  • How important are bacteriocins in structuring the microbiome over leaf, plant, and field scales?
  • How can we translate the specific killing activities of bacteriocins into robust and sustainable phytopathogen control strategies?


Hockett KL and Baltrus DA. 2017. Use of the soft-agar overlay technique to screen for bacterially-produced inhibitory compounds. Journal of Visual Experiments, (119): e55064. doi:10.3791/55064

Arendt KR, Hockett KL, Araldi-Brondolo SJ, Baltrus DA, Arnold AE. 2016. Isolation of endohyphal bacteria from foliar ascomycota and in vitro establishment of their symbiotic associations. Applied and Environmental Microbiology, 82(10): 2943-2949. doi: 10.1128/AEM.00452-16

Hockett KL, Renner T, and Baltrus DA. 2015. Independent co-option of a tailed bacteriophage into a killing complex in Pseudomonas. mBio, 6(4): e00452-15. doi: 10.1128/mBio.00452-15

Baltrus DA, Hendry TA, and Hockett KL. 2014. Ecological genomics of Pseudomonas syringae. In Genomics of Plant-Associated Bacteria, D.C. Gross, A. Lichens-Park, C. Kole (Eds.). Berlin: Springer. 59-77. doi: 10.1007/978-3-642-55378-3_3

Hockett KL, Nishimura MT, Karlsrud E, Dougherty K, and Baltrus DA. 2014. Pseudomonas syringae CC1557: a highly virulent strain with an unusually small type III effector repertoire that includes a novel effector. Molecular Plant-Microbe Interactions, 27(9): 923-932. doi: 10.1094/MPMI-11-13-0354-R

Hockett KL, Ionescu M, and Lindow SE. 2014. Involvement of rppH in thermoregulation in Pseudomonas syringae. Journal of Bacteriology, 196(12): 2313-2322. doi: 10.1128/JB.00057-14

Stockwell VO, Davis EW, Carey A, Shaffer BT, Mavrodi DV, Hassan KA, Hockett KL, Thomashow LS, Paulsen IT, and Loper JE. 2013. pA506, a conjugative plasmid of the plant epiphyte Pseudomonas fluorescens A506. Applied and Environmental Microbiology, 79(17): 5272-5282. doi: 10.1128/AEM.01354-13

Hockett KL, Burch AY, and Lindow SE. 2013. Thermo-regulation of genes mediating motility and plant interactions in Pseudomonas syringae. PLoS ONE, 8(3): e59850. doi: 10.1371/journal.pone.0059850


Naïve Bayes Classifiers and accompanying dataset for Pseudomonas syringae isolate characterization
Scientific data, Fautt, Chad, Couradeau, Estelle, Hockett, Kevin, 2024

Manipulating Agaricus bisporus developmental patterns by passaging microbial communities in complex substrates
Microbiology spectrum, Vieira, Fabricio Rocha, Di Tomassi, Isako, Tomassi, Isako Di, O'Connor, Eoin, Bull, Carolee T., Pecchia, John A., Hockett, Kevin, 2023

Passaging Phyllosphere Microbial Communities Develop Suppression Towards Bacterial Speck Disease in Tomato
Phytobiomes Journal, Ehau-Taumaunu, Hanareia, Hockett, Kevin L., 2023

Aerosolized Hydrogen Peroxide Decontamination of N95 Respirators, with Fit-Testing and Viral Inactivation, Demonstrates Feasibility for Reuse during the COVID-19 Pandemic
mSphere, Derr, Thomas, James, Melissa, Kuny, Chad, Patel, Devanshi, Kendell, Prem, Kandel, Prem, Field, Cassandra, Beckman, Matthew, Hockett, Kevin L., Bates, Mark, Sutton, Troy, Szpara, Moriah L., 2022

Transcriptional Profiles of a Foliar Fungal Endophyte (Pestalotiopsis, Ascomycota) and Its Bacterial Symbiont (Luteibacter, Gammaproteobacteria) Reveal Sulfur Exchange and Growth Regulation during Early Phases of Symbiotic Interaction
mSystems, Shaffer, Justin P., Carter, Morgan E., Spraker, Joseph E., Clark, Meara, Smith, Brian A., Hockett, Kevin L., Baltrus, David A., Elizabeth Arnold, A., 2022

Prophylactic Application of Tailocins Prevents Infection by Pseudomonas syringae
Phytopathology, Baltrus, David A., Clark, Meara, Hockett, Kevin L., Mollico, Madison, Smith, Caitlin, Weaver, Savannah, 2022

Genome Mining Shows Ubiquitous Presence and Extensive Diversity of Toxin-Antitoxin Systems in Pseudomonas syringae
Frontiers in Microbiology, Kandel, Prem P., Naumova, Marina, Fautt, Chad, Patel, Ravikumar R., Triplett, Lindsay R., Hockett, Kevin L., 2022

Ewingella americana: An Emerging Multifaceted Pathogen of Edible Mushrooms
Phytopathology, Hamidizade, Mozhde, Taghavi, S. Mohsen, Moallem, Mahsa, Aeini, Milad, Fazliarab, Amal, Abachi, Hamid, Herschlag, Rachel, Hockett, Kevin L., Bull, Carolee T., Osdaghi, Ebrahim, 2022

Rapid niche shifts in bacteria following conditioning in novel soil environments
Functional Ecology, Yates, Caylon, Trexler, Ryan, Bonet, Idalys, King, William, Hockett, Kevin, Bell, Terrence, 2022

The plant host environment influences competitive interactions between bacterial pathogens
Environmental Microbiology Reports, Ehau-Taumaunu, Hanareia, Hockett, Kevin L., 2022

Prophylactic Application of Tailocins Prevents Infection by Pseudomonas syringae.
Phytopathology, Baltrus, David, Clark, Meara, Hockett, Kevin, Mollico, Madison, Smith, Caitlin, Weaver, Savannah, 2021

Pseudomonas syringae pv. Phaseolicola uses distinct modes of stationary-phase persistence to survive bacteriocin and streptomycin treatments
mBio, Patel, Ravikumar R., Kandel, Prem P., Traverso, Eboni, Hockett, Kevin L., Triplett, Lindsay R., 2021

First Report of Brown Spot on White Button Mushroom (Agaricus bisporus) Caused by Cedecea neteri in Iran
Plant Disease, Hamidzade, Mozhde, Hamidizade, Mozhde, Mohsen Taghavi, S., Taghavi, Moshen, Taghavi, S., Mafakheri, Hamzeh, Herschlag, Rachel, Martins, Samuel, Hockett, Kevin, Bull, Carolee, Osdaghi, Ebrahim, 2021

Pseudomonas can survive tailocin killing via persistence-like and heterogenous resistance mechanisms
Journal of Bacteriology, Kandel, Prem P., Baltrus, David A., Hockett, Kevin L., 2020

Not all Viruses are Bad: Controlling Mushroom Blotch Disease with Bacteriophages
Mushroom News, Ahmad, Abdelmonim, Hockett, Kevin, Bull, C, 2020

Bacterial brown pit, a new disease of edible mushrooms caused by mycetocola sp.
Plant Disease, Hamidizade, Mozhde, Taghavi, S. Mohsen, Martins, Samuel J., Herschlag, Rachel A., Hockett, Kevin L., Bull, Carolee T., Osdaghi, Ebrahim, 2020

Comparing approaches for capturing bacterial assemblages associated with symptomatic (Bacterial Blotch) and asymptomatic mushroom (Agaricus bisporus) caps
Phytobiomes Journal, Martins, Samuel, Trexler, Ryan, Vieira, Fabricio R., Pecchia, John A., Kandel, Prem, Hockett, Kevin L., Bell, Terrence H., Bull, Carolee T., 2020

Localized recombination drives diversification of killing spectra for phage-derived syringacins
ISME Journal, Baltrus, David A., Clark, Meara, Smith, Caitlin, Hockett, Kevin L., 2019

The Inherent Conflicts in Developing Soil Microbial Inoculants
Trends in Biotechnology, Kaminsky, Laura M., Trexler, Ryan V., Malik, Rondy J., Hockett, Kevin L., Bell, Terrence H., 2019

100 years since Tolaas: Bacterial blotch of mushrooms in the 21st century
Plant Disease, Osdaghi, Ebrahim, Martins, Samuel, Ramos-Sepulveda, Laura, Vieira, Fabrício Rocha, Rocha Vieira, Fabrício, Pecchia, John A., Beyer, David, Bell, Terrence H., Yang, Yinong, Hockett, Kevin L., Bull, Carolee T., 2019

Bacterial Brown Pit, a New Disease of Edible Mushrooms Caused by Mycetocola sp.
Plant Disease, Hamidizade, Mozhde, Taghavi, Mohsen, Martins, Samuel, Herschlag, Rachel, Hockett, Kevin, Bull, Carolee, Osdaghi, Ebrahim, 2019

Factoring Ecological, Societal, and Economic Considerations into Inoculant Development
Trends in Biotechnology, Bell, Terrence H, Kaminsky, Laura, Gugino, Beth K, Carlson, John E, Malik, Rondy, Hockett, Kevin, Trexler, Ryan, 2019

Manipulating Wild and Tamed Phytobiomes: Challenges and Opportunities
Phytobiomes Journal, Collins, Alyssa, Bell, Terrence H, Hockett, Kevin, Esker, P, Alcala-Briseno, Ricardo, Gugino, B, Alcalá-Briseño, Ricardo, Barbercheck, Mary, Peter, K, Beattie, Gwyn, Bruns, Mary Ann, Carlson, John, Chung, Taejung, Collins, A, Emmett, Bryan, Esker, Paul, Garrett, Karen, Glenna, Leland, Gugino, Beth K., Del Mar Jiménez-Gasco, María, del Mar Jimenez Gasco, M, Jimenez Gasco, Maria del Mar, Kinkel, Linda, Kovac, Jasna, Kowalski, Kurt, Kowalski, Kurt, Leveau, Johan, Myrick, J, Kuldau, Gretchen, Peter, K, Leveau, Johan, Michalska-Smith, Matthew, Salazar, Maria, Myrick, Jessica, Shade, Ashley, Peter, Kari, Stopnisek, Nejc, Tan, Xiaoqing, Vivanco Salazar, Maria fernanda, Salazar, Maria, Shade, Ashley, Welty, Amy, Stopinsek, Nejc, Stopnisek, Nejc, Wickings, Kyle, Yergeau, Etienne, Tan, Xiaoqing, Welty, Amy, Wickings, Kyle, Wickings, Etienne, Yergeau, Etienne, 2019

Localized Recombination Drives Diversification of Killing Spectra for Phage Derived Syringacins
ISME Journal, Baltrus, David, Clark, Mera, Smith, Caitlin, Hockett, Kevin, 2018

Use of the soft-agar overlay technique to screen for bacterially produced inhibitory compounds
Journal of Visualized Experiments, Hockett, Kevin L., Baltrus, David A., 2017

Isolation of endohyphal bacteria from foliar Ascomycota and In Vitro establishment of their symbiotic associations
Applied and Environmental Microbiology, Arendt, Kayla R., Hockett, Kevin L., Araldi-Brondolo, Sarah J., Baltrus, David A., Arnold, A. Elizabeth, 2016

Independent co-option of a tailed bacteriophage into a killing complex in Pseudomonas
mBio, Hockett, Kevin L., Renner, Tanya, Baltrus, David A., 2015

Pseudomonas syringae CC1557: A highly virulent strain with an unusually small type iii effector repertoire that includes a novel effector
Molecular Plant-Microbe Interactions, Hockett, Kevin L., Nishimura, Marc T., Karlsrud, Erick, Dougherty, Kevin, Baltrus, David A., 2014

Ecological genomics of pseudomonas syringae, Baltrus, David A., Hendry, Tory A., Hockett, Kevin L., 2014

Involvement of rppH in thermoregulation in Pseudomonas syringae
Journal of Bacteriology, Hockett, Kevin L., Ionescu, Michael, Lindow, Steven E., 2014