Decoupling of ammonium regulation and ntcA transcription in the diazotrophic marine cyanobacterium Trichodesmium sp. IMS101
- 22 September 2011
- journal article
- research article
- Published by Oxford University Press (OUP) in The ISME Journal
- Vol. 6 (3), 629-637
- https://doi.org/10.1038/ismej.2011.121
Abstract
Nitrogen (N) physiology in the marine cyanobacterium Trichodesmium IMS101 was studied along with transcript accumulation of the N-regulatory gene ntcA and of two of its target genes: napA (nitrate assimilation) and nifH (N2 fixation). N2 fixation was impaired in the presence of nitrite, nitrate and urea. Strain IMS101 was capable of growth on these combined N sources at nifH accumulated under nitrogen-fixing conditions; these transcript levels were maintained in the presence of nitrate (100 μM) and ammonium (20 μM). However, nifH transcript levels were below detection at ammonium concentrations >20 μM. napA mRNA was found at low levels in both N2-fixing and ammonium-utilizing filaments, and it accumulated in filaments grown with nitrate. The positive effect of nitrate on napA transcription was abolished by ammonium additions of >200 μM. This effect was restored upon addition of the glutamine synthetase inhibitor L-methionin-DL-sulfoximine. Surprisingly, ntcA transcript levels remained high in the presence of ammonium, even at elevated concentrations. These findings indicate that ammonium repression is decoupled from transcriptional activation of ntcA in Trichodesmium IMS101.This publication has 63 references indexed in Scilit:
- Metabolic streamlining in an open-ocean nitrogen-fixing cyanobacteriumNature, 2010
- Role of Two NtcA-Binding Sites in the Complex ntcA Gene Promoter of the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120Journal of Bacteriology, 2008
- Globally Distributed Uncultivated Oceanic N 2 -Fixing Cyanobacteria Lack Oxygenic Photosystem IIScience, 2008
- Expression of the nitrogen stress response gene ntcA reveals nitrogen-sufficient Synechococcus populations in the oligotrophic northern Red SeaLimnology and Oceanography, 2005
- 2‐Oxoglutarate increases the binding affinity of the NtcA (nitrogen control) transcription factor for the Synechococcus glnA promoterFEBS Letters, 2002
- NUTRIENT CONTROLS ON NITROGEN UPTAKE AND METABOLISM BY NATURAL POPULATIONS AND CULTURES OF TRICHODESMIUM (CYANOBACTERIA)Journal of Phycology, 2001
- Ecological Aspects of ntcA Gene Expression and Its Use as an Indicator of the Nitrogen Status of Marine Synechococcus sppApplied and Environmental Microbiology, 2001
- ALKALINE PHOSPHATASE ACTIVITIES AMONG POPULATIONS OF THE COLONY‐FORMING DIAZOTROPHIC CYANOBACTERIUM TRICHODESMIUM SPP. (CYANOBACTERIA) IN THE RED SEAJournal of Phycology, 2001
- Cloning and transcriptional analysis of the nifUHDK genes of Trichodesmium sp. IMS101 reveals stable nifD, nifDK and nifK transcriptsMicrobiology, 1998
- Molecular Mechanisms of Loss of β2-Microglobulin Expression in Drug-Resistant Breast Cancer Sublines and Its Involvement in Drug ResistanceBiochemistry, 1998