11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 6: Ecological and Evolutionary Genomics of Coral Reef Organisms
6-10
Thermal Regulation in Coral Larvae: A Microarray Screening
Mauricio RODRIGUEZ-LANETTY* 1,2 , Saki HARII 3 , Ove HOEGH-GULDBERG 1
1 Centre for Marine Studies, University of Queensland, Brisbane, Australia, 2 Department
of Biology, University of Louisiana at lafayette, Lafayette, 3 Graduate School of
Engineering and Science, University of Ryukyus, Naha, Japan
Coral reefs around the world are in decline with much of the mortality attributed to coral
bleaching – the loss of photosynthetic algal symbionts – resulting from global warming.
To understand how corals may respond to the current global warming threat, we need to
understand how the coral/algal symbiont responds to the increase of sea water
temperature not only on an organismic and physiological level but also on a molecular
and cellular level. Microarrays are currently being shown to be an adequate tool to
explore and screen for molecular pathways that are affected and change in response to
increases in temperature. In this study, we have conducted a microarray experiment to
document the changes of gene expression that occur in the coral host cell during the first
hours of thermal stress. This study focuses on determining the direct effect of
temperature on the host cell and not those secondary effects arising from physiological
impaired algal symbionts after being exposed to high temperature. In order to dissect
these two effects with different origins, we conducted our thermal stress experiments on
aposymbiotic (lacking of symbiont) coral larvae from the scleractinian coral Acropora
millepora. Results from this study show the cellular dynamics of coral larvae gene
expression in the first hours after being challenged in a thermal stress experiment.
6-11
The Genomic Bases Of Stress Tolerance And Temperature Adaptation in Corals
Eli MEYER* 1 , Shi WANG 1 , Galina AGLYAMOVA 1 , Mikhail MATZ 1
1 Biological Sciences, University of Texas, Austin, Austin, TX
Reef building corals are extremely sensitive to thermal stress, but the potential for these
ecologically important animals to adapt to increasing ocean temperatures remains
uncertain. We are characterizing the genetically determined natural variation in
responses to thermal stress and settlement cues to better understand the traits under
selection during climate change. We used reciprocal crosses between colonies of the
coral Acropora millepora to produce larvae that we maintained in culture at standard
(28°C) and constant elevated temperatures (32°C). Direct measures of thermal tolerance
were obtained from measurement of survival during short (2 d) periods of temperature
stress (34°C). These different stress phenotypes were further characterized by measuring
changes in protein content and RNA:DNA ratios during development and growth under
these conditions. Physiological measurements of metabolic activity and temperature
response were simultaneously obtained for large numbers of individual larvae, allowing
estimation of individual, genetically determined, and environmentally induced variation
within a single experiment. To understand the genomic bases of these responses, we are
sequencing the larval transcriptome and measuring global gene expression profiles.
These profiles, in combination with the whole-genome genotyping methods currently
being developed in our lab, will allow us to establish links between genetic markers, gene
expression, and thermal tolerance. These data will help to build a framework for
understanding the long-term impacts of climate change on coral reefs.
6-12
Using A Stressed-Focused Microarray To Characterize Coral Responses To Copper
Michael MORGAN* 1 , Sara EDGE 2 , Alexander VENN 3 , Ross JONES 3
1 Berry College, Mount Berry, GA, 2 Harbor Branch Oceanographic Institute, Ft. Pierce, FL,
3 Bermuda Institute of Ocean Sciences, Ferry Reach, St George's, Bermuda
Copper is a well recognized marine pollutant, having been used extensively in antifouling paints
of boats. In corals it is known to induce bleaching at very low concentrations, but the
mechanism associated with this response, and how it differs from warm-water induced
bleaching of corals is presently unknown. A stress-focused microarray composed of 153 genes
was used to investigate which coral genes are most responsive to copper. In this study, small
fragments of Montastraea franksi were exposed to different concentrations of copper (0, 0.3,
3.0, and 30 ppb) for various exposure periods (2 h, 24 h, and 7 d). Exposure treatments were
conducted under natural light in temperature controlled, Teflon®, dosing chambers developed
at the Bermuda Institute of Ocean Sciences (BIOS). Some coral stress genes on this microarray
have previously demonstrated responses to elevated copper concentrations. Results presented
will illustrate how this study represents a first attempt to characterize the expression profiles of
various genes (a) under different concentrations of copper (b) on different temporal scales and
(c) within and between colonies.
6-13
Microarray Characterization Of Gene Expression in montastraea Cavernosa Through
Space And Time
Sara EDGE* 1 , Michael MORGAN 2 , Joshua VOSS 1 , Terry SNELL 3
1 Robertson Coral Reef Program, Harbor Branch Oceanographic Institute at Florida Atlantic
University, Fort Pierce, FL, 2 Department of Biology, Berry College, Mount Berry, GA, 3 School
of Biology, Georgia Institute of Technology, Atlanta, GA
Coral communities are increasingly impacted by a variety of natural and anthropogenic
stressors acting on local or global scales. Based on the nature of stress and scale of impact,
corals exhibit variable responses. Through the application of microarray technology, gene
expression profiles can be used to diagnose stressors impacting coral populations in the field.
Changes in gene expression are key elements of the stress response, often occurring before
physiological damage is evident. Furthermore, responses such as bleaching or tissue loss may
result from a multitude of factors, whereas the regulation of gene expression can be directly
related to the causative agent of stress. In this study, a stress-focused microarray was used to
detect gene expression patterns of Montastraea cavernosa on South Florida reefs at different
sites over a fifteen month period. The array consisted of 148 genes involved in a variety of
cellular functions, ranging from metabolism and development to the regulation of apoptosis and
the stress response. Gene expression patterns revealed a strongly significant, episodic stress
response at three of the five sites investigated. In addition, a significant correlation between the
expression of symbiont genes and the expression of coral stress response genes was evident
across all dates and sites. To our knowledge, this is the first study to use a Cnidarian microarray
to detect changes in the physiological condition of coral in the field associated with seasonal
events as well as point source stress.
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