A unicellular cyanobacterium relies on sodium energetics to fix N₂.

ABSTRACT: Diazotrophic cyanobacteria can fix nitrogen gas (N₂) but are usually scarce in nitrogen-limited coastal waters, which poses an apparent ecological paradox. One hypothesis is that high salinities (> 10 g/L NaCl) may inhibit cyanobacterial N₂ fixation. However, here we show that N₂ fixation in a unicellular coastal cyanobacterium exclusively depends on sodium ions and is inhibited at low NaCl concentrations (< 4 g/L). In the absence of Na⁺, cells of Cyanothece sp. ATCC 51142 (recently reclassified as Crocosphaera subtropica) upregulate the expression of nifHDK genes and synthesise a higher amount of nitrogenase, but do not fix N₂ and do not grow. We find that the loss of N₂-fixing ability in the absence of Na⁺ is du

SUBMITTER: Tang S 

PROVIDER: S-EPMC11550448 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature