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The transcriptional regulation of the glyoxylate cycle in SAR11 in response to iron fertilization in the Southern Ocean


Beier, S and Galvez, MJ and Molina, V and Sarthou, G and Queroue, F and Blain, S and Obernosterer, I, The transcriptional regulation of the glyoxylate cycle in SAR11 in response to iron fertilization in the Southern Ocean, Environmental Microbiology Reports, 7, (3) pp. 427-434. ISSN 1758-2229 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

DOI: doi:10.1111/1758-2229.12267


The tricarboxylic acid (TCA) cycle is a central metabolic pathway that is present in all aerobic organisms and initiates the respiration of organic material. The glyoxylate cycle is a variation of the TCA cycle, where organic material is recycled for subsequent assimilation into cell material instead of being released as carbon dioxide. Despite the importance for the fate of organic matter, the environmental factors that induce the glyoxylate cycle in microbial communities remain poorly understood. In this study, we assessed the expression of isocitrate lyase, the enzyme that induces the switch to the glyoxylate cycle, of the ubiquitous SAR11 clade in response to natural iron fertilization in the Southern Ocean. The cell-specific transcriptional regulation of the glyoxylate cycle, as determined by the ratio between copy numbers of isocitrate lyase gene transcripts and isocitrate genes, was consistently lower in iron fertilized than in high-nutrient, low chlorophyll waters (by 2.4- to 16.5-fold). SAR11 cell-specific isocitrate lyase gene transcription was negatively correlated to chlorophyll a, and bulk bacterial heterotrophic metabolism. We conclude that the glyoxylate cycle is a metabolic strategy for SAR11 that is highly sensitive to the degree of iron and carbon limitation in the marine environment.

Item Details

Item Type:Refereed Article
Keywords:tricarboxylic acid (TCA) cycle, glyoxylate cycle, iron fertilization, Southern Ocean
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Measurement and assessment of marine water quality and condition
UTAS Author:Queroue, F (Mr Fabien Queroue)
ID Code:105913
Year Published:2015
Web of Science® Times Cited:8
Deposited By:IMAS Research and Education Centre
Deposited On:2016-01-20
Last Modified:2016-09-21

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