Real-time PCR reveals a high incidence of Symbiodinium clade D at low levels in four scleractinian corals across the Great Barrier Reef: implications for symbiont shuffling

By Jos C. Mieog, M. V. Oppen, Neal E. Cantin, W. Stam, Jeanine L. Olsen. Coral reefs, 2007

243 citations recorded by the source corpus.

Reef corals form associations with an array of genetically and physiologically distinct endosymbionts from the genus Symbiodinium. Some corals harbor different clades of symbionts simultaneously, and over time the relative abundances of these clades may change through a process called symbiont shuffling. It is hypothesized that this process provides a mechanism for corals to respond to environmental threats such as global warming. However, only a minority of coral species have been found to harbor more than one symbiont clade simultaneously and the current view is that the potential for symbiont shuffling is limited. Using a newly developed real-time PCR assay, this paper demonstrates that previous studies have underestimated the presence of background symbionts because of the low sensitivity of the techniques used. The assay used here targets the multi-copy rDNA ITS1 region and is able to detect Symbiodinium clades C and D with >100-fold higher sensitivity compared to conventional techniques. Technical considerations relating to intragenomic variation, estimating copy number and non-symbiotic contamination are discussed. Eighty-two colonies from four common scleractinian species (Acropora millepora, Acropora tenuis, Stylophora pistillata and Turbinaria reniformis) and 11 locations on the Great Barrier Reef were tested for background Symbiodinium clades. Although these colonies had been previously identified as harboring only a single clade based on SSCP analyses, background clades were detected in 78% of the samples, indicating that the potential for symbiont shuffling may be much larger than currently thought.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/8211e9db784b0b3a88eb910bc3253a4cf5f585a6

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Citations in the corpus

One-year survey of a single Micronesian reef reveals extraordinarily rich diversity of Symbiodinium types in soritid foraminifera (2007, background): “Given that Symbiodinium types occurring at less than 5– 10% of the total symbiont population will not be detected by DGGE (Thornhill et al. 2006), it may also be possible that considerable cryptic symbiont diversity exists at undetectable levels (Baker 2003; Mieog et al. 2007).”
Acclimation and adaptation of scleractinian coral communities along environmental gradients within an Indonesian reef system (2010, unknown): “The presence of clade D in the most marginal environment where temperatures reach 34 °C, and comparisonwith previous studies (Rowan, 2004; Mieog et al., 2007; Mostafavi et al., 2007; LaJeunesse et al., 2010), infers that clade D here is thermally tolerant.”
Identifying the World's Most Climate Change Vulnerable Species: A Systematic Trait-Based Assessment of all Birds, Amphibians and Corals (2013, background): “Typically one clade may be dominant and the others may be present at low to very low abundance [51].”
Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook (2008, background): “Nonetheless, the growing number of studies documenting these changes in response to bleaching events, and the increasing number of reef coral species found to be capable of hosting Symbiodinium in clade D (Mieog et al., 2007) indicate that these changes do indeed occur and are likely to be important”
Tradeoffs to Thermal Acclimation: Energetics and Reproduction of a Reef Coral with Heat Tolerant Symbiodinium Type-D (2011, background): “A recent study utilizing novel molecular methods has revealed previously undetectable levels (<5–10%) of thermally tolerant symbionts types in four species of reef corals [5], raising the possibility that many species may be able to acclimatize to climate change in this way [6, 7].”
Community dynamics and physiology of Symbiodinium spp. before, during, and after a coral bleaching event (2014, background): “By using DGGE methodology, our study is unable to give absolute abundances of individual Symbiodinium phylotypes.”
Patterns of Symbiodinium distribution in three giant clam species across the biodiverse Bird’s Head region of Indonesia (2012, background): “Future applications of more sensitive molecular methods that are designed to identify Symbiodinium in low abundance (such as quantitative PCR) may re veal additional symbiont diversity within individual clams (Mieog et al. 2007, Correa et al. 2009).”