Project description:Coral reefs are declining globally. Temperature anomalies disrupt coral-algal symbioses at the molecular level, causing bleaching and mortality events. In terrestrial mutualisms, diversity in pairings of host and symbiont individuals (genotypes) results in ecologically and evolutionarily relevant stress response differences. The extent to which such intraspecific diversity provides functional variation in coral-algal systems is unknown. Here we assessed functional diversity among unique pairings of coral and algal individuals (holobionts). We targeted six genetically distinct Acropora palmata coral colonies that all associated with a single, clonal Symbiodinium ‘fitti’ strain in a natural common garden. No other species of algae or other strains of S. ‘fitti’ could be detected in host tissues. When colony branches were experimentally exposed to cold stress, host genotype influenced the photochemical efficiency of the symbiont strain, buffering the stress response to varying degrees. Gene expression differences among host individuals with buffered vs. non-buffered symbiont responses included biochemical pathways that mediate iron availability and oxygen stress signaling—critical components of molecular interactions with photosynthetic symbionts. Spawning patterns among hosts reflected symbiont performance differences under stress. These data are some of the first to indicate that genetic interactions below the species level affect coral holobiont performance. Intraspecific diversity serves as an important but overlooked source of physiological variation in this system, contributing raw material available to natural selection. Note: in the final publication, only ambient and cold treatments are discussed, but there was an additional hot treatment for each genotype at 34C. Most colonies expired after 6 hours, so PAM data could not be collected. The microarray data from 3.5 hours are included here.
Project description:In this study transcriptomic data of three life history stages of Orciraptor agilis was generated: 1) Gliding cells in absence of food ('gliding'), 2) Cells attached to the cell wall of its algal prey during perforation ('fattacking'), 3) Cells after acquisition of the algal plastid material ('digesting'). Furthermore, RNA-seq of the algal prey Mougeotia sp. was also performed. A de novo transcriptome assembly of the algal reads was performed in order to identify and substract algal reads of the Orciraptor samples by mapping the Orciraptor reads to the algal transcriptome. After this filtering step the remaining Orciraptor reads from all libraries were pooled for a de novo transcriptome assembly of Orciraptor agilis. This transcriptome was the basis for a comparative transcriptomic study in which transcript expression was compared between the three life history stages.