Fungal parasites infecting N<sub>2</sub>-fixing cyanobacteria reshape carbon and N<sub>2</sub> fixation and trophic transfer.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41484120.
- Also identified by DOI 10.1038/s41467-025-67818-x and PMC identifier 12775406.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Fungal parasites are associated with bloom-forming algae, yet their impact on N<sub>2</sub> fixation and the fate of newly fixed nitrogen during cyanobacterial blooms is poorly understood. We report infections on the ecologically important N<sub>2</sub>-fixing cyanobacterium Dolichospermum (formerly Anabaena) in the Baltic Sea. Using single-cell isotope probing, microscopy, and biogeochemical analyses, we examine how infections affect carbon and N<sub>2</sub> fixation and elemental transfer within a natural community. Fungal sporangia infect up to 80% of filaments, mostly targeting storage cells (akinetes, 82% prevalence) and N<sub>2</sub>-fixing cells (heterocytes, 44%), but rarely vegetative cells (5%). Infections at akinete-heterocyte junctions extract 4- and 10-fold more carbon and nitrogen than those on vegetative cells, reducing host storage by 28% and 56%. Overall, 22% of newly fixed nitrogen is transferred to fungi, comparable to heterotrophic bacteria. Infections also occur in Nodularia and Aphanizomenon, suggesting fungi-like parasitism broadly affects bloom dynamics and the fate of new nitrogen.
Medical subject headings
- Nitrogen Fixation
- Carbon
- Cyanobacteria
- Fungi
- Anabaena