Parasites of Planktothrix; cyanophages and chytrids as top-down regulators in a Lake Erie Embayment

Session: Harmful Algal Blooms: From Ecosystem Drivers to Ecosystem Impacts (4)

Katelyn McKindles, Bowling Green State University, [email protected]
Makayla Manes, Bowling Green State University, [email protected]
Robert (Mike) McKay, University of Windsor, [email protected]
Timothy Davis, Bowling Green State University, [email protected]
George Bullerjahn, Bowling Green State University, [email protected]

Abstract

Planktothrix agardhii consistently dominates the harmful algal bloom population in Sandusky Bay, Lake Erie (USA) from May until September each year. This filamentous cyanobacterial genus has a few known parasites; the cyanophage PaV-LD (Lake Dunghu, China), and the chytrid fungal species Rhizophydium megarrhizum sp. Chy-Kol 2008 (Lake Kolbotnvatnet, Norway). The purpose of our work has been to establish how these parasitic interactions affect the host population, specifically during a bloom. Metatranscriptomic data from the 2015 bloom year indicates the presence of endemic variants of both of these pathogens. Utilizing dilution and single filament isolation techniques, 8 chytrid isolates have been obtained for characterization, including host specificity on 20 Planktothrix agardhii isolates and modes of pathogenesis. In parallel work, wild viral stocks were obtained via a modified cation-charged filtration technique. These stocks are then used to establish potential host-viral interactions and for viral purification through multiple rounds of infections. Continuing work will take an ‘omics approach at understanding the spatial and temporal prevalence of phage and chytrid infection as well as relationships between chytrid host range and secondary metabolite production.