Rachel Penczykowski

Assistant Professor of Biology
Principal Investigator, Plant Disease Team

Rachel Penczykowski is a disease ecologist who studies how environmental change affects the ecology and evolution of infectious diseases at different spatial scales, in particular how climate variation impacts plant-pathogen interactions. She runs a welcoming lab and enjoys introducing the research process to new people. 

“I was shaped by having fantastic mentors myself, going back to when I worked in a lab washing dishes, breeding fruit flies, and learning how to do PCR (polymerase chain reaction) as a high schooler. I was fortunate to work with people who were very patient and wanted to show me the process of science. I had mentors who took the time to show me the bigger picture and then the nuts and bolts, telling me how the experiment got its start, the backstory which might be quite different from the version that goes into the methods section of a paper.  

I've tried to be intentional in our lab, giving glimpses into what my job is and how the different parts of what we are doing fit together as a whole. I try to give the context for what was done on the front end that led us to where we are now. What were some of the decisions we made? Which were grounded in ecological and evolutionary theory and which were made because we had no choice and this was what we had? There is a bit of both. 

When I started my lab at WashU, I planned to focus on powdery mildew infections of Plantago lanceolata host plants, because that was the host species I had worked with in my postdoc. I spent a very frustrating field season trying to find enough populations of Plantago lanceolata with powdery mildew to study. I kept going to all these parks and saying, ‘Ah! There's Plantago lanceolata here, but it's not infected. This other stupid Plantago species that I don't care about is covered with mildew. If only I studied that one instead!’ It took me a year-and-a-half of that to say, ‘Hold it. What if I also study the Plantago species that's clearly winning at this mildew infection game?’ (Well, the plants are not winning.) That turned out to be a more sensible and very interesting route for us.”