This dissertation characterizes the genetic diversity and thermal tolerance of the coral
holobiont Stylophora pistillata and Pocillopora verrucosa (family Pocilloporidae)
across the Saudi Arabian Red Sea coast (~1500 km). The population genetic structure
and holobiont diversity was assessed using genome-wide single nucleotide
polymorphisms (SNPs) identified with reference genome-based RAD-Seq, while the
associated microbial communities of the algal symbiont (Symbiodiniaceae) and
bacteria were inferred from metabarcoding analyses of the ITS2 and 16S rRNA gene.
Thermal tolerance of Stylophora pistillata colonies was assessed using standardized
short-term heat stress assays on the novel Coral Bleaching Automated Stress System
(CBASS).
Chapter 1 details the assembly and annotation of the P. verrucosa genome (~380 Mbp;
27,439 gene models), which was highly complete and compared well to the already
available S. pistillata genome. Chapter 2 presents population genetic analyses of both
coral species, which revealed pronounced differences in their population genetic
structure. While P. verrucosa seemed to be highly connected across the Red Sea basin
with the exception of the far south, S. pistillata depicted a complex population genetic
structure. Microbial communities of Symbiodiniaceae and bacteria were overall less
diverse in P. verrucosa than in S. pistillata, and followed an association pattern that
was partly determined by the environment and partly by host genotype. Chapter 3
identifies thermally tolerant S. pistillata genotypes by comparing the heat stress
response of colonies collected at two sites within the same reef. Ex-situ heat-stress
assays confirmed that colonies from the more temperature stable site (fore reef) were
less thermally tolerant than their conspecifics from the back reef, where the diel
temperature is more variable. This chapter also highlights the utility of acute heat-stress
assays as a tool to identify thermotolerant colonies.
Taken together, the work of this dissertation provides a foundation for coral
conservation in the Red Sea. It highlights that the genetic structure differs between coral
species, suggesting that effective conservation through marine protected areas need to
incorporate data from multiple species. Coral population genetic data should further be
complemented by thermal tolerance assays across the Red Sea to associate genetic
diversity with patterns of heat stress tolerance.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/670794 |
| Date | 07 1900 |
| Creators | Buitrago-López, Carol |
| Contributors | Voolstra, Christian R., Biological and Environmental Science and Engineering (BESE) Division, Aranda, Manuel, Tester, Mark A., Davies, Sarah |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2023-02-25, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation will become available to the public after the expiration of the embargo on 2023-02-25. |
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