CAARL · Comparative Genomics and Environmental Diversity of Coral Associated Apicomplexa-Related Lineages
FP7 — People (Marie Curie Actions)
- Duration
- 2014-01-01 → 2016-12-31
- EU contribution
- €221,192
- Participants
- 1
- Scheme
- MC-IOF
Lines connect the coordinator with its partners.
Results in brief
Comparative Genomics and Environmental Diversity of Coral Associated Apicomplexa-Related Lineages
Coral reefs are home to the greatest density of species in shallow marine waters, including diverse microbial communities. However, almost everything we know about reef microbial communities is confined to prokaryotes and viruses: next to nothing is known about the microbial eukaryotes (protists), with the exception of Symbiodinium. Symbiodinium (a dinoflagellate) forms an endosymbiotic interaction with coral that is critical to reef health: coral bleaching is the stress-related expulsion of Symbiodinium, and is a global threat to reef diversity. Beyond Symbiodinium, we know little about reef protist communities, how they interact with corals and other microbes, or the interplay between protists, environmental gradients, and coral health. We have used 18S high-throughput sequencing to characterize the microeukaryotic community associated to corals other from Symbiodinium. Using an approach in which we excluded the metazoan signal from our datasets we have been able to identify two major protists groups associated to corals that are not the zooxanthella, the Apicomplexan Symbiont N and the Syndiniales. As well, we have been able to describe the diversity of protists belonging to the coral microbiome which signal was previously masked by the metazoan signal. Furthermore, we have studied the alga Ostreobium, that is known to be associated to corals but is still unclear if its role is beneficiary or pernicious to the animal. We have been able to retrieve its 18S rDNA sequence and its chloroplast genome. We have improved the phylogenetic placement of Ostreobium by using plastid genes and the 18S and we have characterized its biogeographical distribution using the 16S plastid gene. Overall, we have expanded our knowledge on the coral associated protist communities beyond Symbiodinium, opening new venues for future research on coral ecology and physiology as well as protist evolution and ecology.
Data: CORDIS, © European Union
Project objective
Coral reefs are home to the greatest density of species in shallow marine waters, including unusually diverse microbial communities. However, almost everything we know about reef microbial communities is confined to prokaryotes and viruses: next to nothing is known about the microbial eukaryotes, with the exception of the symbiont dinoflagellate Symbiodinium. Coral reefs are like most other marine environments, where protists are consistently overlooked. Chromera and Vitrella are two reef-associated algae assumed to have a symbiotic relationship similar to that of Symbiodinium. As photosynthetic relatives of apicomplexan parasites, they held answers to long-debated questions about plastid evolution, but equally important questions about their functional relationship to corals and the reef community have hardly been asked. It has been observed that bacterial sequence surveys are heavily ‘contaminated’ with eukaryotic plastid sequences. The apicomplexanrelated lineages (ARLs) are the richest source of still-unidentified plastid diversity, and virtually all of this diversity is restricted to coral reefs. We know they exist, but have no direct information on their biology or role in ecosystems whatsoever. ARL-V is the most common lineage, but we cannot even say whether the organisms are photosynthetic symbionts or intracellular parasites. To address these questions, an ecological approach was needed.
Original text from CORDIS.
Participants
- AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS · MadridCoordinatorSpain
Links
Data: CORDIS, © European Union