Multi-omics approach to identify a microbial biomarker for Planktothrix-dominated cyanobacterial harmful algal blooms in freshwater lakes

The global frequency and duration of cyanobacterial blooms are increasing, posing threats to drinking water supplies, disrupting recreational activities, and disturbing ecosystems. Planktothrix, a filamentous cyanobacterium, is responsible for blooms worldwide and produces toxic secondary metabolites. Water parameters such as temperature, pH, turbidity, and nitrogen and phosphorus concentrations have been reported to influence Planktothrix blooms. However, there is still a lack of in-depth understanding regarding key microbial players of bloom dynamics and their symbiotic and competitive interactions within Planktothrix-dominated bloom. Therefore, we conducted biweekly surveillance over a three-year period in Grand Lake St. Marys in Ohio, USA, a freshwater lake with historical dominance of Planktothrix. We analyzed physicochemical parameters, toxins, and the fungal and bacterial microbiome using amplicon sequencing, along with functional analysis using shotgun metagenomics. The integrated analysis of the multi-omics data revealed a potential interaction among nitrogen-related bacteria, methane-producing archaea, and algicidal fungi/bacteria, with carbon- and nitrogen-associated metabolic capability serving as connecting factors. In addition, Rhodobacter, a purple non-sulfur bacterium, emerged as a candidate biomarker to predict Planktothrix-dominated blooms, showing a consistent negative association with Planktothrix as well as with the toxin-producing mcyE gene abundance. Further studies to validate functional interactions across microbial players are warranted.

Primary Presenter: Dae-Wook Kang, University of Toledo (daewook.kang@utoledo.edu)

Authors:

Mashuk Siddiquee, University of Toledo  (Mashuk.Siddiquee@rockets.utoledo.edu)

Sara Cornelius, University of Toledo  (Sara.Cornelius@rockets.utoledo.edu)

Mike Sudman Jr., Celina Water Treatment Plant  (msudman@celinaohio.org)

Vansh Patel, University of Toledo  (Vansh.Patel@utoledo.edu)

Youngwoo Seo, University of Toledo  (youngwoo.seo@utoledo.edu)

Thomas Bridgeman, University of Toledo  (Thomas.Bridgeman@utoledo.edu)

Dae-Wook Kang, University of Toledo  (daewook.kang@utoledo.edu)