Microorganisms facilitate uptake of dissolved organic nitrogen by seagrass leaves

Flavia Tarquinio, Jeremy Bourgoure, Annette Koenders, Bonnie Laverock, Christin Säwström, Glenn A. Hyndes

Research output: Contribution to journalComment/debate

15 Citations (Scopus)


Microorganisms play a critical role in nitrogen cycling by mineralising dissolved organic nitrogen (DON) compounds into bioavailable inorganic forms (DIN). Although DIN is crucial for seagrass growth, the hypothesis that seagrass leaf associated-microorganisms could convert DON to forms available for plant uptake has never been tested. We conducted a laboratory-based experiment in which seagrass (Posidonia sinuosa) leaves were incubated with 15N-amino acids (aa), with and without associated microorganisms. Samples were collected after 0.5, 2, 6 and 12 h. Both bulk stable isotope and nanoscale secondary ion mass spectrometry (NanoSIMS) analysis showed high accumulation of 15N within seagrass leaf tissues with an associated microbiota, but not in plants devoid of microorganisms. These results significantly change our understanding of the mechanisms of seagrass nitrogen use and provide evidence that seagrass microbiota increase nitrogen availability for uptake by seagrass leaves by mineralising aa, thus enhancing growth and productivity of these important coastal ecosystems.

Original languageEnglish
Pages (from-to)2796–2800
Number of pages5
JournalISME Journal
Issue number11
Publication statusE-pub ahead of print - 5 Jul 2018
Externally publishedYes

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