In hospite Symbiodinium photophysiology and antioxidant responses in Acropora muricata on a coast-reef scale: implications for variable bleaching patterns

Louis, Yohan Didier; Kaullysing, Deepeeka; Gopeechund, Arvind; Mattan-Moorgawa, Sushma; Bahorun, Theeshan; Dyall, Sabrina D.; Bhagooli, Ranjeet

doi:10.1007/s13199-016-0380-4

Cited by 28 publications

(29 citation statements)

References 40 publications

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“…Lin et al [15] reported that the S. kawagutii genome contains diverse set of antioxidative response genes such as SOD and ascorbate peroxidases. While most of the studies on SOD and CAT enzymes in Symbiodinium suggested these enzymes play a major role in coping with an increase of sea temperature to prevent coral bleaching [91][92][93], a number of studies in other organisms revealed that these enzymes may act in response to other types of environmental stress such as salinity, exposure to hydrogen peroxide and drought conditions [94][95][96]. Apart from the antioxidative response, cell adhesion proteins also play a role in maintaining coral-Symbiodinium symbiosis interaction [9].…”

Section: Symbiosismentioning

confidence: 99%

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

Akbar

Ali

Usup

et al. 2018

JMSE

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Abstract:Dinoflagellates are essential components in marine ecosystems, and they possess two dissimilar flagella to facilitate movement. Dinoflagellates are major components of marine food webs and of extreme importance in balancing the ecosystem energy flux in oceans. They have been reported to be the primary cause of harmful algae bloom (HABs) events around the world, causing seafood poisoning and therefore having a direct impact on human health. Interestingly, dinoflagellates in the genus Symbiodinium are major components of coral reef foundations. Knowledge regarding their genes and genome organization is currently limited due to their large genome size and other genetic and cytological characteristics that hinder whole genome sequencing of dinoflagellates. Transcriptomic approaches and genetic analyses have been employed to unravel the physiological and metabolic characteristics of dinoflagellates and their complexity. In this review, we summarize the current knowledge and findings from transcriptomic studies to understand the cell growth, effects on environmental stress, toxin biosynthesis, dynamic of HABs, phylogeny and endosymbiosis of dinoflagellates. With the advancement of high throughput sequencing technologies and lower cost of sequencing, transcriptomic approaches will likely deepen our understanding in other aspects of dinoflagellates' molecular biology such as gene functional analysis, systems biology and development of model organisms.

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Section: Symbiosismentioning

confidence: 99%

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

Akbar

Ali

Usup

et al. 2018

JMSE

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“…Some evidence does suggest that processes operating within a species across a depth gradient also potentially operate over time; for example, the maximum photochemical efficiency (F v /F m ) for Symbiodinium in hospite of corals within shallow reefs are often driven to annual low yields in summer (Warner et al, 2002;Ulstrup et al, 2008). Most likely these lows in summer reflect long-term downregulation in response to warmer waters and high PAR in summer (Warner et al, 2002) that is also accompanied by an increase in photoprotection through nonphotochemical quenching (Ulstrup et al, 2008;Sawall et al, 2014;Louis et al, 2016). However, Hill and Ralph (2005) suggest that the same non-photochemical mechanisms for photoprotection to high-light exposure during the diel solar peak in key species of shallow water Great Barrier Reef corals are active across seasons and independent of temperature.…”

Section: Introductionmentioning

confidence: 99%

Utility of Photochemical Traits as Diagnostics of Thermal Tolerance amongst Great Barrier Reef Corals

et al. 2018

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Light availability is considered a key factor regulating the thermal sensitivity of reef building corals, where excessive excitation of photosystem II (PSII) further exacerbates pressure on photochemical pathways already compromised by heat stress. Coral symbionts acclimate to changes in light availability (photoacclimation) by continually fine-tuning the photochemical operating efficiency of PSII. However, how this process adjusts throughout the warmest months in naturally heat-tolerant or sensitive species is unknown, and whether this influences the capacity to tolerate transient heat stress is untested. We therefore examined the PSII photophysiology of 10 coral species (with known thermal tolerances) from shallow reef environments at Heron Island (Great Barrier Reef, Australia), in spring (October-November, 2015) vs. summer (February-March, 2016). Corals were maintained in flow-through aquaria and rapid light curve (RLC) protocols using pulse amplitude modulated (PAM) fluorometry captured changes in the PSII photoacclimation strategy, characterized as the minimum saturating irradiance (E k ), and the extent of photochemical ([1 -C], operating efficiency) vs. non-photochemical ([1 -Q]) energy dissipation. Values of E k across species were >2-fold higher in all coral species in spring, consistent with a climate of higher overall light exposure (i.e., higher PAR from lower cloud cover, rainfall and wind speed) compared with summer. Summer decreases in E k were combined with a shift toward preferential photochemical quenching in all species. All coral species were subsequently subjected to thermal stress assays. An equivalent temperature-ramping profile of 1 • C increase per day and then maintenance at 32 • C was applied in each season. Despite the significant seasonal photoacclimation, the species hierarchy of thermal tolerance [maximum quantum yields of PSII (F v /F m ), monitored at dawn and dusk] did not shift between seasons, except for Pocillopora damicornis (faster declines in summer) and Stylophora pistillata (total mortality in spring). Furthermore, the strategy for dealing with light energy (i.e., preferential photochemical vs. non-photochemical quenching) was unchanged for thermally tolerant species across seasons, whereas thermally sensitive species switched between preferential [1 -Q] and [1 -C] from spring to summer. We discuss how such traits can potentially be used as a diagnostic of thermal tolerance under non-stressed conditions.

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“…Many studies have evaluated the acclimatization responses of coral species to different thermal environments (e.g. Jokiel & Coles 1977, Brown et al 2002, Schoepf et al 2015a, Louis et al 2016) and some have evaluated adaptation to thermal exposure over meaningful ecological time (McClanahan & Maina 2003, Guest et al 2012, Baker et al 2013, Pratchett et al 2013, McClanahan & Muthiga 2014. Studies of changing sensitivity over time are critical to resolving this issue and, to date, suggest that some generic adaptation is occurring (but see Hughes et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Changes in coral sensitivity to thermal anomalies

McClanahan¹

2017

Mar. Ecol. Prog. Ser.

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The 1998 and 2016 thermal anomalies were among the 2 most severe global-scale anomalies in recent history, with broad-scale impacts on reef condition. In 2 Kenyan fully protected national park reef lagoons, the water flow, light, and temperature exposure severity of these 2 events was grossly similar at 7.3 cm s -1 , ~50 Einsteins m −2 d −1 and ~85 degree-days above summer baseline. Yet, despite similarities in the coral communities' metrics over this time, the bleaching responses were diminished considerably across this 17 yr period. For example, the numbers of pale and bleached colonies declined from 73 to 27% and from 96 to 60% in the low and high thermal exposure reefs, respectively. A metric that weights bleaching by the intensity of the response and the number of individuals of each taxon also found a decline from 35 to 10% and from 65 to 33%. Of the 21 most common coral taxa, 11, including major contributors to coral cover such as Porites and Acropora, showed declines in their sensitivity. Ten taxa, including Montipora and Pocillopora, showed either little or weak evidence for change in sensitivity, and 1 taxon, Acanthastrea, was more sensitive to the exposure in 2016 than in 1998. Sampling limitations and qualitative differences in the pre-peak temperature conditions did not allow separating the influences of genetic adaptation, acclimatization, and community change.

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In hospite Symbiodinium photophysiology and antioxidant responses in Acropora muricata on a coast-reef scale: implications for variable bleaching patterns

Cited by 28 publications

References 40 publications

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

Utility of Photochemical Traits as Diagnostics of Thermal Tolerance amongst Great Barrier Reef Corals

Changes in coral sensitivity to thermal anomalies

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