Kevin L. Hockett, Ph.D.

Research

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?

Publications

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