Salt Shock Responses of Microcystis Revealed through Physiological, Transcript, and Metabolomic Analyses

Type Article
Date 2020-03
Language English
Author(s) Georges Des Aulnois Maxime1, Réveillon Damien1, Robert Elise1, Caruana Amandine1, Briand Enora1, Guljamow Arthur2, Dittmann Elke2, Amzil Zouher1, Bormans Myriam3
Affiliation(s) 1 : IFREMER-Phycotoxins Laboratory, IFREMER, F-44311 Nantes, France
2 : Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany
3 : UMR CNRS 6553 ECOBIO, University of Rennes, 35042 Rennes, France
Source Toxins (2072-6651) (MDPI AG), 2020-03 , Vol. 12 , N. 3 , P. 192 (18p.)
DOI 10.3390/toxins12030192
Note This article belongs to the Special Issue Environmental Drivers of Algal and Cyanobacterial Toxin Dynamics
Keyword(s) Microcystis aeruginosa, microcystin, salt stress, metabolomic, transcript
Abstract

The transfer of Microcystis aeruginosa from freshwater to estuaries has been described worldwide and salinity is reported as the main factor controlling the expansion of M. aeruginosa to coastal environments. Analyzing the expression levels of targeted genes and employing both targeted and non-targeted metabolomic approaches, this study investigated the e ect of a sudden salt increase on the physiological and metabolic responses of two toxic M. aeruginosa strains separately isolated from fresh and brackish waters, respectively, PCC 7820 and 7806. Supported by di erences in gene expressions and metabolic profiles, salt tolerance was found to be strain specific. An increase in salinity decreased the growth of M. aeruginosa with a lesser impact on the brackish strain. The production of intracellular microcystin variants in response to salt stress correlated well to the growth rate for both strains. Furthermore, the release of microcystins into the surrounding medium only occurred at the highest salinity treatment when cell lysis occurred. This study suggests that the physiological responses of M. aeruginosa involve the accumulation of common metabolites but that the intraspecific salt tolerance is based on the accumulation of specific metabolites. While one of these was determined to be sucrose, many others remain to be identified. Taken together, these results provide evidence that M. aeruginosa is relatively salt tolerant in the mesohaline zone and microcystin (MC) release only occurs when the capacity of the cells to deal with salt increase is exceeded.

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Georges Des Aulnois Maxime, Réveillon Damien, Robert Elise, Caruana Amandine, Briand Enora, Guljamow Arthur, Dittmann Elke, Amzil Zouher, Bormans Myriam (2020). Salt Shock Responses of Microcystis Revealed through Physiological, Transcript, and Metabolomic Analyses. Toxins, 12(3), 192 (18p.). Publisher's official version : https://doi.org/10.3390/toxins12030192 , Open Access version : https://archimer.ifremer.fr/doc/00615/72689/