Secondary nectar alkaloids impact the growth of microbial taxa preset in nectar.
Abstract
Plant secondary metabolites (PSMs) are widely recognized for their defensive and signaling roles in plant–herbivore interactions, but their influence on nectar-associated microbial communities is only just beginning to be understood. Nectar microbes are important players in plant-pollinator interactions, as they can alter key nectar characteristics such as sugar composition, pH, and scent profiles, affecting pollinator behavior and plant reproductive success. The extent to which floral PSMs structure nectar microbiomes represents an important gap in our understanding of plant-pollinator interactions and the selective forces giving rise to floral PSMs. This project aimed to determine whether two toxic floral alkaloids PSMs – caffeine & nicotine – affect microbial growth, testing the hypothesis that these compounds should inhibit microbial growth in a concentration-dependent manner. We cultured common taxa of nectar-associated yeast and bacteria in synthetic nectar media treated with varying concentrations of each alkaloid. We observed taxon- and concentration-dependent inhibition across both alkaloids, suggesting that these compounds may function as chemical filters of microbial community composition. By demonstrating that plant secondary chemistry structures nectar microbiomes, this study fills a key gap in chemical ecology and advances understanding of plant–pollinator–microbe interactions, with implications for floral trait evolution and pollination dynamics.
Start Time
15-4-2026 11:00 AM
End Time
15-4-2026 12:00 PM
Room Number
219
Presentation Type
Oral Presentation
Presentation Subtype
UG Orals
Presentation Category
Science, Technology, and Engineering
Student Type
Undergraduate
Faculty Mentor
Melissa Whitaker
Secondary nectar alkaloids impact the growth of microbial taxa preset in nectar.
219
Plant secondary metabolites (PSMs) are widely recognized for their defensive and signaling roles in plant–herbivore interactions, but their influence on nectar-associated microbial communities is only just beginning to be understood. Nectar microbes are important players in plant-pollinator interactions, as they can alter key nectar characteristics such as sugar composition, pH, and scent profiles, affecting pollinator behavior and plant reproductive success. The extent to which floral PSMs structure nectar microbiomes represents an important gap in our understanding of plant-pollinator interactions and the selective forces giving rise to floral PSMs. This project aimed to determine whether two toxic floral alkaloids PSMs – caffeine & nicotine – affect microbial growth, testing the hypothesis that these compounds should inhibit microbial growth in a concentration-dependent manner. We cultured common taxa of nectar-associated yeast and bacteria in synthetic nectar media treated with varying concentrations of each alkaloid. We observed taxon- and concentration-dependent inhibition across both alkaloids, suggesting that these compounds may function as chemical filters of microbial community composition. By demonstrating that plant secondary chemistry structures nectar microbiomes, this study fills a key gap in chemical ecology and advances understanding of plant–pollinator–microbe interactions, with implications for floral trait evolution and pollination dynamics.
