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Symbiodinium sp cells produce light-induced intra- and extracellular singlet oxygen, which mediates photodamage of the photosynthetic apparatus and has the potential to interact with the animal host in coral symbiosis

Rehman, Ateeq Ur and Szabó, Milán and Deák, Zsuzsanna and Sass, László and Larkum, Anthony and Vass, Imre (2016) Symbiodinium sp cells produce light-induced intra- and extracellular singlet oxygen, which mediates photodamage of the photosynthetic apparatus and has the potential to interact with the animal host in coral symbiosis. NEW PHYTOLOGIST, 212 (2). pp. 472-484. ISSN 0028-646X

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Abstract

Coral bleaching is an important environmental phenomenon, whose mechanism has not yet been clarified. The involvement of reactive oxygen species (ROS) has been implicated, but direct evidence of what species are involved, their location and their mechanisms of production remains unknown. Histidine-mediated chemical trapping and singlet oxygen sensor green (SOSG) were used to detect intra- and extracellular singlet oxygen (O-1(2)) in Symbiodinium cultures. Inhibition of the Calvin-Benson cycle by thermal stress or high light promotes intracellular O-1(2) formation. Histidine addition, which decreases the amount of intracellular O-1(2), provides partial protection against photosystem II photoinactivation and chlorophyll (Chl) bleaching. O-1(2) production also occurs in cell-free medium of Symbiodinium cultures, an effect that is enhanced under heat and light stress and can be attributed to the excretion of O-1(2)-sensitizing metabolites from the cells. Confocal microscopy imaging using SOSG showed most extracellular O-1(2) around the cell surface, but it is also produced across the medium distant from the cells. We demonstrate, for the first time, both intra- and extracellular O-1(2) production in Symbiodinium cultures. Intracellular O-1(2) is associated with photosystem II photodamage and pigment bleaching, whereas extracellular O-1(2) has the potential to mediate the breakdown of symbiotic interaction between zooxanthellae and their animal host during coral bleaching.

Item Type: Article
Uncontrolled Keywords: GENUS SYMBIODINIUM; ARABIDOPSIS-THALIANA; ULTRAVIOLET-RADIATION; CHLAMYDOMONAS-REINHARDTII; HEAT-STRESS; NITRIC-OXIDE; oxidative stress; PHOTOSYSTEM-II; Synechocystis PCC 6803; II REACTION CENTERS; Symbiodinium; singlet oxygen (O-1(2)); photosystem II (PSII); PHOTOINHIBITION; coral bleaching; ALGAE
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia
SWORD Depositor: MTMT SWORD
Depositing User: MTMT SWORD
Date Deposited: 31 Jan 2017 14:46
Last Modified: 31 Jan 2017 14:47
URI: http://real.mtak.hu/id/eprint/47033

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