Victoria Swiler
Swiler, Victoria
Year: 2022
Faculty Advisor: Joyce Van Eck

“Understanding the Roles of Auxin and Ethylene in Physalis grisea Fruit Drop”

Project Summary:

Physalis grisea (groundcherry) is a fruit crop native to North America and is an underutilized species. Groundcherry easily drops its fruit through a process known as abscission, allowing it to disperse seed and shed injured organs. This process occurs at the abscission zone (AZ) on the pedicel, which is the stalk that attaches fruit to the plant stem. However, large amounts of fruit abscission result in a loss of profit for farmers. To develop groundcherry varieties with reduced fruit drop, we first need to understand the mechanisms behind P. grisea fruit abscission.

Auxin and ethylene are plant hormones known to be implicated in organ abscission in other species. However, this has not been confirmed in any Physalis species. My goal is to understand the role of auxin and ethylene in P. grisea fruit abscission. I hypothesized that applying auxin to groundcherry pedicels will delay fruit abscission and ethylene will accelerate abscission. Furthermore, auxin applied distally will delay abscission more than proximally.

To accomplish this, I applied auxin distally and proximally to the AZ to groundcherry pedicels and applied ethylene to the entire pedicel. Data were collected twice a day by counting the number of abscised pedicels and fruit. Data analysis confirmed that applying auxin to groundcherry pedicels delayed abscission, especially when applied distally. Also, ethylene application accelerated abscission. These results confirm that auxin and ethylene have similar effects on fruit abscission as in other species. This experiment will be useful in the future to determine if these hormones affect abscission differently in abscission-edited groundcherry lines.

My Experience:

Over the summer, I gained an incredible amount of professional and lab experience and made lifelong friends. I had the opportunity to do CRISPR editing, work with an underutilized crop species, and perform my own experiment under a wonderful mentor. I also learned about professional development through workshops on communication and social science. There were also seminars from PIs at Cornell and BTI where I could learn about other types of research in the field. Finally, I enjoyed learning about graduate school at Cornell and thinking about what I want out of my career in the future.