DEVELOPMENT AND APPLICATION OF A LARGE-SCALE PANGENOMIC FRAMEWORK FOR THE STUDY OF CYANOHAB TAXON MICROCYSTIS

Cyanobacterial harmful algal blooms of species, such as the common and often toxigenic Microcystis, are predicted to increase in frequency and magnitude as nutrient loading and global warming impact freshwater system, this negatively affecting food webs, ecosystem function, and fresh water access globally. Historically, ecological characterization and managing risks[JEB1]  associated with this problematic taxon has been clouded by cryptic morphological and genetic diversity. Morphology of Microcystis may shift with environmental conditions, while genetic classification (e.g., 16S) indicates a single species with multiple ecotypes. Leveraging large-scale pangenome analyses that integrate hundreds of genomes, we established a robust framework that resolves previously hidden biodiversity in Microcystis. We identified 26 genome clusters, 16 of which qualify for species demarcation, that serve as the basis for examining functional trait variation between species. For example, this framework enabled resolution of 4 species with the toxin trait, containing all 10 genes required for microcystin synthesis, while 11 species lacked all microcystin synthesis genes. Interestingly, we resolved a single species containing both toxic and non-toxic genotypes which may reflect loss of the trait in a single species. Similar analyses for other ecotype characteristics are underway. Overall, we describe a valuable framework to integrate large datasets to resolve historical discrepancies in the classification of aquatic taxa and its application to improve the study of a globally problematic taxon.

Presentation Preference: Oral

Primary Presenter: Chris McLimans, University of Oklahoma (cmclimans@ou.edu)

Authors:

Jessica Beyer, University of Oklahoma  (beyer@ou.edu)

K. David Hambright, University of Oklahoma  (dhambright@ou.edu)