biostudies-literatureAbada ASimons FoundationThe Angel Faivovich Foundation for Ecological Research The Weizmann SABRA - Yeda-Sela - WRC Program The Estate of Emile Mimran, and the Maurice and Vivienne Wohl Biology EndowmentEuropean Research CouncilThe Dean of Faculty fellowship The Sir Charles Clore Postdoctoral FellowshipMinerva FoundationThe Weizmann SAERI program1167-1183https://www.ebi.ac.uk/biostudies/studies/S-EPMC10356946biostudies-literatureUnknown17(8)Microbial interactions govern marine biogeochemistry. These interactions are generally considered to rely on exchange of organic molecules. Here we report on a novel inorganic route of microbial communication, showing that algal-bacterial interactions between Phaeobacter inhibens bacteria and Gephyrocapsa huxleyi algae are mediated through inorganic nitrogen exchange. Under oxygen-rich conditions, aerobic bacteria reduce algal-secreted nitrite to nitric oxide (NO) through denitrification, a well-studied anaerobic respiratory mechanism. The bacterial NO is involved in triggering a cascade in algae akin to programmed cell death. During death, algae further generate NO, thereby propagating the signal in the algal population. Eventually, the algal population collapses, similar to the sudden deThe ISME journalAerobic bacteria produce nitric oxide via denitrification and promote algal population collapse.PMC10356946622065101075514Huang Zhang ILipsman VSperfeld MBabbin ARRocha JCarmieli RAbada ABeiralas RSegev EDuchin-Rapp YCohen BNarvaez DYuda LBen-Dor SfalseAerobic bacteria produce nitric oxide via denitrification and promote algal population collapse.Microbial interactions govern marine biogeochemistry. These interactions are generally considered to rely on exchange of organic molecules. Here we report on a novel inorganic route of microbial communication, showing that algal-bacterial interactions between Phaeobacter inhibens bacteria and Gephyrocapsa huxleyi algae are mediated through inorganic nitrogen exchange. Under oxygen-rich conditions, aerobic bacteria reduce algal-secreted nitrite to nitric oxide (NO) through denitrification, a well-studied anaerobic respiratory mechanism. The bacterial NO is involved in triggering a cascade in algae akin to programmed cell death. During death, algae further generate NO, thereby propagating the signal in the algal population. Eventually, the algal population collapses, similar to the sudden de2023-01-01T00:00:00Z2023 Aug2026-03-18T14:07:07.475Z2025-08-23T03:08:58.251ZS-EPMC103569463717338310.1038/s41396-023-01427-8