Kazamia, Elena, Czesnick, Hjördis, Nguyen, Thi Thanh Van, Croft, Martin T., Sherwood, Emma, Sasso, Severin, Hodson, Sarah James, Warren, Martin J., Smith, Alison G. (2012) Mutualistic interactions between vitamin B12 -dependent algae and heterotrophic bacteria exhibit regulation. Environmental Microbiology, 14 (6). pp. 1466-1476. ISSN 1462-2912. (doi:10.1111/j.1462-2920.2012.02733.x) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:34196)
The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. | |
Official URL: http://dx.doi.org/10.1111/j.1462-2920.2012.02733.x |
Abstract
Many algae are auxotrophs for vitamin B(12) (cobalamin), which they need as a cofactor for B(12) -dependent methionine synthase (METH). Because only prokaryotes can synthesize the cobalamin, they must be the ultimate source of the vitamin. In the laboratory, a direct interaction between algae and heterotrophic bacteria has been shown, with bacteria supplying cobalamin in exchange for fixed carbon. Here we establish a system to study this interaction at the molecular level. In a culture of a B(12) -dependent green alga Chlamydomonas nivalis, we found a contaminating bacterium, identified by 16S rRNA analysis as Mesorhizobium sp. Using the sequenced strain of M.?loti (MAFF303099), we found that it was able to support the growth of B(12) -dependent Lobomonas rostrata, another green alga, in return for fixed carbon. The two organisms form a stable equilibrium in terms of population numbers, which is maintained over many generations in semi-continuous culture, indicating a degree of regulation. However, addition of either vitamin B(12) or a carbon source for the bacteria perturbs the equilibrium, demonstrating that the symbiosis is mutualistic and facultative. Chlamydomonas reinhardtii does not require B(12) for growth because it encodes a B(12) -independent methionine synthase, METE, the gene for which is suppressed by addition of exogenous B(12) . Co-culturing C.?reinhardtii with M.?loti also results in reduction of METE expression, demonstrating that the bacterium can deliver the vitamin to this B(12) -independent alga. We discuss the implications of this for the widespread distribution of cobalamin auxotrophy in the algal kingdom.
Item Type: | Article |
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DOI/Identification number: | 10.1111/j.1462-2920.2012.02733.x |
Subjects: | Q Science |
Divisions: | Divisions > Division of Natural Sciences > Biosciences |
Depositing User: | Lin Riches |
Date Deposited: | 06 Jun 2013 14:53 UTC |
Last Modified: | 16 Nov 2021 10:11 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/34196 (The current URI for this page, for reference purposes) |
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