Distinct dissolved organic matter sources induce rapid transcriptional responses in coexisting populations of Prochlorococcus, Pelagibacter and the OM60 clade

Adrian K. Sharma, Jamie W. Becker, Elizabeth A. Ottesen, Jessica A. Bryant, Solange Duhamel, David M. Karl, Otto X. Cordero, Daniel J. Repeta, Edward F. Delong

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

A considerable fraction of the Earth's organic carbon exists in dissolved form in seawater. To investigate the roles of planktonic marine microbes in the biogeochemical cycling of this dissolved organic matter (DOM), we performed controlled seawater incubation experiments and followed the responses of an oligotrophic surface water microbial assemblage to perturbations with DOM derived from an axenic culture of Prochlorococcus, or high-molecular weight DOM concentrated from nearby surface waters. The rapid transcriptional responses of both Prochlorococcus and Pelagibacter populations suggested the utilization of organic nitrogen compounds common to both DOM treatments. Along with these responses, both populations demonstrated decreases in gene transcripts associated with nitrogen stress, including those involved in ammonium acquisition. In contrast, responses from low abundance organisms of the NOR5/OM60 gammaproteobacteria were observed later in the experiment, and included elevated levels of gene transcripts associated with polysaccharide uptake and oxidation. In total, these results suggest that numerically dominant oligotrophic microbes rapidly acquire nitrogen from commonly available organic sources, and also point to an important role for carbohydrates found within the DOM pool for sustaining the less abundant microorganisms in these oligotrophic systems.

Original languageEnglish (US)
Pages (from-to)2815-2830
Number of pages16
JournalEnvironmental Microbiology
Volume16
Issue number9
DOIs
StatePublished - Sep 2014
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics

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