Postdoctoral Fellowship: PRFB: Eco-evolutionary impacts of cyanobacterial diets on host-parasite interactions

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2025. The fellowship supports research and training of the fellow that will contribute to biology in innovative ways. Ponds and lakes are experiencing increases in harmful algal bloom (HAB) events globally.

Cyanobacteria capable of forming HABs produce compounds that can be toxic to pond-dwelling organisms. However, these toxins can help these organisms protect themselves from parasites. Since the frequency of HABs is increasing, many generations of pond-dwelling organisms may consume them for their benefit against parasites.

This research will investigate how HABs affect disease epidemics in pond-dwelling organisms, which is important from both an ecological and public health perspective. The fellow will receive training in genetic and evolutionary techniques. This research will advance our knowledge on how HABs may change patterns of disease in lakes and ponds and how cyanotoxins work against fungal pathogens.

Furthermore, the fellow will support the training and professional development of future scientists.

Phytoplankton secondary metabolites can protect aquatic hosts from disease. However, how these medicinal diets shape host population dynamics, parasite evolution, and parasite epidemics in nature is still unknown. This research will focus on how phytoplankton can influence disease dynamics in freshwater ecosystems using the Daphnia-parasite system.

First, this project aims to uncover the molecular basis for parasite susceptibility in the Daphnia-Metschnikowia host-parasite system and determine whether susceptibility is related to gut enzyme profile and genes. This will be done using quantitative trait mapping and genome wide association approaches to locate susceptibility genes by focusing on chymotrypsin and trypsin genes which are the target of cyanobacterial peptides.

This will be combined with liquid chromatography-mass spectrometry to identify gut enzyme profiles associated with parasite susceptibility in Daphnia. This research will also explore if medicinal cyanobacterial diets select for more virulent parasites by conducting evolution experiments with two different parasites of Daphnia. These two parasites have different infection mechanisms and are impacted differently by medicinal cyanobacterial diets, providing an opportunity to observe differences in virulence selection.

Lastly, this project will also look at parasite epidemics of Daphnia communities in ponds along a gradient of urbanization to detect patterns in the phytoplankton communities that may be either facilitating or impeding disease in Daphnia in this system of ponds. The fellow will train in genomics, population genetics and experimental evolution to address eco-evolutionary research questions.

Broader impacts activities will include research training for undergraduate and graduate students, professional development for graduate students and postdoctoral researchers, and outreach initiatives.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.