Strain level differences in marine microbial parasite-host metabolites and host mortality dynamics

ABSTRACT:

Parasitism is a widespread source of mortality among marine microbial communities, with members of the diverse alveolate group Syndiniales being most prevalent and frequently identified in global omics studies. Despite their ubiquity, not much is known about Syndiniales parasite-host infection dynamics, strain-level variability, or biogeochemical impacts of metabolites released via infection and lysis. Here, we performed culture-based experiments to compare the infection of Scrippsiella acuminata by two strains of Syndiniales within the genus Amoebophrya sp. (strains 4401 and 4390). To examine changes in metabolite composition and identify important compounds released over an infection cycle, we collected exudates daily for 4 days from both parasite-host pairings and performed untargeted metabolomics using liquid chromatography-mass spectrometry. Samples were also collected daily for flow cytometry to estimate changes in parasite/host abundances and the percentage of infected hosts. Metabolite composition varied between Amoebophrya strains and exhibited distinct temporal patterns and significant differences between infected vs. host (or spore-only) treatments. Specific compounds were more indicative of host infection, as revealed through differential analysis and log2 fold changes. Physiological differences were also recorded at the strain level, with parasite strain 4401 exhibiting a more traditional infection cycle characterized by rapid host infection (38% infected by day 3), decreased host abundance over time, and the release of new spores on days 3-4. In comparison, strain 4390 had a more extended infection timeline, as evidenced by lower host mortality (12% infected by day 3) over a single infection cycle. This work provides novel insights into the biogeochemistry and physiology of widespread marine microbial parasites and reinforces the importance of considering strain-level infection dynamics that may drive mortality in microbial food webs.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse phase

PROVIDER: MTBLS11219 | MetaboLights | 2026-10-05

REPOSITORIES: MetaboLights