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Coordinated regulation of growth, activity and transcription in natural populations of the unicellular nitrogen-fixing cyanobacterium Crocosphaera

Lookup NU author(s): Professor Sam Wilson

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Abstract

© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.The temporal dynamics of phytoplankton growth and activity have large impacts on fluxes of matter and energy, yet obtaining in situ metabolic measurements of sufficient resolution for even dominant microorganisms remains a considerable challenge. We performed Lagrangian diel sampling with synoptic measurements of population abundances, dinitrogen (N"2) fixation, mortality, productivity, export and transcription in a bloom of Crocosphaera over eight days in the North Pacific Subtropical Gyre (NPSG). Quantitative transcriptomic analyses revealed clear diel oscillations in transcript abundances for 34% of Crocosphaera genes identified, reflecting a systematic progression of gene expression in diverse metabolic pathways. Significant time-lagged correspondence was evident between nifH transcript abundance and maximal N"2 fixation, as well as sepF transcript abundance and cell division, demonstrating the utility of transcriptomics to predict the occurrence and timing of physiological and biogeochemical processes in natural populations. Indirect estimates of carbon fixation by Crocosphaera were equivalent to 11% of net community production, suggesting that under bloom conditions this diazotroph has a considerable impact on the wider carbon cycle. Our cross-scale synthesis of molecular, population and community-wide data underscores the tightly coordinated in situ metabolism of the keystone N"2-fixing cyanobacterium Crocosphaera, as well as the broader ecosystem-wide implications of its activities.

Publication metadata

Author(s): Wilson ST, Aylward FO, Ribalet F, Barone B, Casey JR, Connell PE, Eppley JM, Ferron S, Fitzsimmons JN, Hayes CT, Romano AE, Turk-Kubo KA, Vislova A, Virginia Armbrust E, Caron DA, Church MJ, Zehr JP, Karl DM, De Long EF

Publication type: Article

Publication status: Published

Journal: Nature Microbiology

Year: 2017

Volume: 2

Online publication date: 31/07/2017

Acceptance date: 23/06/2017

ISSN (electronic): 2058-5276

Publisher: Nature Publishing Group

URL: https://doi.org/10.1038/nmicrobiol.2017.118

DOI: 10.1038/nmicrobiol.2017.118

PubMed id: 28758990

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