Genetics of Harpin Perception in Nonhost Plants

Abstract:
Phytopathogenic bacteria infect plant cells by deploying virulence proteins through their needle-like protein secretion machinery. Plants, in turn, have developed specialized recognition mechanisms to mount an immune response to these virulence proteins. This immune response is typically a rapid and localized cell death response, termed the hypersensitive response (HR). While almost all HR-triggering bacterial proteins act inside of plant cells, one class of secreted proteins, called harpins, possess the unusual property of triggering an HR from outside the cell. Interestingly, harpin responsiveness is associated with nonhost plant immunity. The plant immunity components mediating harpin recognition and response have remained elusive, despite the first harpin, HrpN from the fire blight bacterium Erwinia amylovora, being discovered over 30 years ago. In this talk, I discuss my progress in unraveling this mystery by probing natural genetic variation in the HrpN cell death response in two fire blight nonhosts, Arabidopsis thaliana and Nicotiana tabacum.

About the Speaker:
Jeremy Held is a Ph.D. candidate working in Dr. Tim McNellis’ lab in the Department of Plant Pathology & Environmental Microbiology. Prior to Penn State, Jeremy obtained his B.S. in Environmental & Plant Biology from Ohio University. His current research interests include plant-microbe interactions, mechanisms of plant defense, and phytopathogenic bacteria. Previous research endeavors include the surveying of genetic diversity of ash tree populations impacted by emerald ash borer (advised by Dr. Jennifer Koch, USDA Forest Service) and the study of plant gravitropic signaling (advised by Dr. Sarah Wyatt, Ohio University).

Contact

Timothy McNellis
twm4@psu.edu