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Heat stress causes inhibition of the de novo synthesis of antenna proteins and photobleaching in cultured Symbiodinium

Takahashi, Shunichi; Whitney, Spencer; Itoh, Shigeru; Maruyama, Tadashi; Badger, Murray

Description

Coral bleaching, caused by heat stress, is accompanied by the light-induced loss of photosynthetic pigments in in situ symbiotic dinoflagellate algae (Symbiodinium spp.). However, the molecular mechanisms responsible for pigment loss are poorly understood. Here, we show that moderate heat stress causes photobleaching through inhibition of the de novo synthesis of intrinsic light-harvesting antennae [chlorophyll a-chlorophyll c2-peridinin- protein complexes (acpPC)] in cultured Symbiodinium...[Show more]

dc.contributor.authorTakahashi, Shunichi
dc.contributor.authorWhitney, Spencer
dc.contributor.authorItoh, Shigeru
dc.contributor.authorMaruyama, Tadashi
dc.contributor.authorBadger, Murray
dc.date.accessioned2015-12-10T22:55:23Z
dc.identifier.issn0027-8424
dc.identifier.urihttp://hdl.handle.net/1885/60089
dc.description.abstractCoral bleaching, caused by heat stress, is accompanied by the light-induced loss of photosynthetic pigments in in situ symbiotic dinoflagellate algae (Symbiodinium spp.). However, the molecular mechanisms responsible for pigment loss are poorly understood. Here, we show that moderate heat stress causes photobleaching through inhibition of the de novo synthesis of intrinsic light-harvesting antennae [chlorophyll a-chlorophyll c2-peridinin- protein complexes (acpPC)] in cultured Symbiodinium algae and that two Clade A Symbiodinium species showing different thermal sensitivities of photobleaching also show differential sensitivity of this key protein synthesis process. Photoinhibition of photosystem II (PSII) and subsequent photobleaching were observed at temperatures of >31°C in cultured Symbiodinium CS-73 cells grown at 25-34°C, but not in cultures of the more thermally tolerant control Symbiodinium species OTcH-1. We found that bleaching in CS-73 is associated with loss of acpPC, which is a major antennae protein in Symbiodinium. In addition, the thermally induced loss of this protein is light-dependent, but does not coincide directly with PSII photoinhibition and is not caused by stimulated degradation of acpPC. In cells treated at 34°C over 24 h, the steady-state acpPC mRNA pool was modestly reduced, by ≈30%, whereas the corresponding synthesis rate of acpPC was diminished by >80%. Our results suggest that photobleaching in Symbiodinium is consequentially linked to the relative susceptibility of PSII to photoinhibition during thermal stress and occurs, at least partially, because of the loss of acpPC via undefined mechanism(s) that hamper the de novo synthesis of acpPC primarily at the translational processing step.
dc.publisherNational Academy of Sciences (USA)
dc.sourcePNAS - Proceedings of the National Academy of Sciences of the United States of America
dc.subjectKeywords: algal protein; antenna protein; chlorophyll; messenger RNA; protein derivative; alga; article; bleaching; cell growth; cladistics; heat stress; light; nonhuman; photoinhibition; photosystem II; priority journal; protein degradation; protein depletion; pro Bleaching; Coral; Photoinhibition; Symbiosis; Zooxanthellae
dc.titleHeat stress causes inhibition of the de novo synthesis of antenna proteins and photobleaching in cultured Symbiodinium
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume105
dc.date.issued2008
local.identifier.absfor060704 - Plant Pathology
local.identifier.absfor060203 - Ecological Physiology
local.identifier.ariespublicationu9204316xPUB521
local.type.statusPublished Version
local.contributor.affiliationTakahashi, Shunichi, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationWhitney, Spencer, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationItoh, Shigeru, Nagoya University
local.contributor.affiliationMaruyama, Tadashi, Japan Marine Science and Technology Center
local.contributor.affiliationBadger, Murray, College of Medicine, Biology and Environment, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue11
local.bibliographicCitation.startpage4203
local.bibliographicCitation.lastpage4208
local.identifier.doi10.1073/pnas.0708554105
dc.date.updated2015-12-10T07:49:48Z
local.identifier.scopusID2-s2.0-41949121273
local.identifier.thomsonID000254263300025
CollectionsANU Research Publications

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