Project description:Endozoicomonas are prevalent, abundant bacterial associates of marine animal hosts, including corals. Their role in holobiont health and functioning, however, remains poorly understood. To identify putative interactions within the coral holobiont, we characterized a novel Endozoicomonas isolate and assessed its transcriptomic and proteomic responses to tissue extracts of its native host, the Red Sea coral Acropora humilis, at control and elevated temperatures. We show that host cues stimulated differential expression of genes assumed to be involved in the modulation of the host immune response by Endozoicomonas, such as flagellar assembly genes, ankyrins, ephrins, and serpins. Proteome analysis revealed the upregulation of vitamin B1 and B6 biosynthetic as well as glycolytic processes by Endozoicomonas in response to host cues. We further demonstrate that the inoculation of A. humilis with its native Endozoicomonas strain resulted in enhanced holobiont health metrics, such as host tissue protein content and algal symbiont photosynthetic efficiency. Behavioral, physiological, and metabolic changes in Endozoicomonas may be key to the onset and function of mutualistic interactions within the coral holobiont, and our results suggest that the priming of Endozoicomonas to a symbiotic lifestyle may involve modulation of host immunity and the exchange of essential metabolites with other holobiont members. Consequently, Endozoicomonas presumably plays an important role in holobiont nutrient cycling and may therefore be implicated in its health, acclimatization, and ecological adaptation.
Project description:This studies investigates the acute response of the coral Acropora millepora to two immunogenes: MDP (bacterial mimic) and pIC (viral mimic). Three members of the GiMAP familly were found to respond strongly to MDP treatment, showing analalogy to the immune response in vertebrates and plants. Differential gene expression following treatment with two immunogenes
Project description:This SuperSeries is composed of the following subset Series: GSE27022: Microarray studies of darkness stress and bleaching in the Caribbean coral Acropora palmata GSE27024: Microarray studies of darkness stress and bleaching in the Caribbean coral Montastraea faveolata Refer to individual Series
Project description:Naval training exercises involving live ordnance can introduce munitions constituents (MCs) such as 1,3,5-trinitro-1,3,5 triazine (RDX) into the marine environment posing a potential environmental hazard to reef organisms, including corals. We developed a bioinformatic infrastructure and high-density microarray for a coral consortium and assessed the effects of RDX bioaccumulation on gene expression related to coral and endosymbiont health in the reef building coral (Acropora formosa). High-throughput sequencing and assembly of the transcriptomes for A. formosa and all eukaryotic endosymbionts yielded 189,616 unique sequences and 25,003 significant functional matches to protein-coding genes. Functional annotation and metabolic pathway associations were also developed. The bioinformatics base was transitioned to custom 15,000 probe microarrays that were used to assess RDX effects on gene expression in the A. formosa coral consortium. Coral fragments were exposed to RDX (0.5, 1, 2, 4, and 8 mg/L) for 5d in a controlled laboratory experiment. RDX readily accumulated into coral tissues; however, bioconcentration was minimal (bioconcentration factor = 1.09-1.50). RDX caused no significant changes in zooxanthellae tissue densities, however a significant (p<0.05) 40% increase in mucocytes was observed in the 8 mg/L exposure indicating a mucosal protective response to RDX exposure. Investigation of T-RFLP profiles indicated significant differences in bacterial community composition inhabiting the coral surface microlayer of Acropora sp. between control and RDX-exposed coral as among exposure concentrations. Differential expression of transcripts increased with increasing RDX concentration where 126, 195 and 272 transcripts were differentially expressed in the 0.5, 2.0 and 8 mg/L RDX treatments, respectively. The commonality in differentially expressed transcripts (DET) among exposure concentrations ranged from 9.9 to 29.0% where the lowest commonality was observed between the most disparate RDX exposure concentrations. Increasing RDX concentrations caused an increasing proportion of the number of transcripts differentially expressed in symbionts relative to corals. Further, a trend toward decreased transcript expression in symbionts in response to increasing RDX concentration was observed where 20.0% of differentially expressed transcripts had decreased expression at the 0.5 mg/L concentration, whereas 80.4% had decreased expression at the 8 mg/L concentration. Investigation of KEGG orthology for DET indicated potential impacts of RDX on a variety of molecular pathways, predominantly in endosymbionts compared to the coral host. Prominent effects of RDX exposure on pathways included enrichment of DET involved in carbohydrate metabolism, amino acid metabolism, energy metabolism, lipid metabolism, metabolism of cofactors and vitamins, environmental information processing and cellular processes. Fragments of the living branched coral Acropora formosa were obtained from Oceans, Reefs and Aquaria (http://www.orafarm.com). Ten gallon aquaria were used to expose 5 coral fragments to control or RDX exposure conditions (0.49, 0.93, 1.77, 3.67 and 7.18 mg/L, measured concentrations). The microarray hybridization experiment included 3 biological replicates for the 0.5, 2, and 8 mg/L RDX conditions and 4 biological replicates for the control.
Project description:Two known settlement/metamorphosis inducing stimuli (crustose coralline algae, and ethanolic extract of crustose coralline algae) and one stimulus which just induces metamorphosis (LWamide) were used to stimulate competent planula larvae of the coral Acropora millepora. Samples were taken 0.5h, 4h and 12h post induction isolate the genes controlling settlement and metamorphosis in this coral.
Project description:Coral reefs are based on the symbiotic relationship between corals and photosynthetic dinoflagellates of the genus Symbiodinium. We followed gene expression of coral larvae of Acropora palmata and Montastraea faveolata after exposure to Symbiodinium strains that differed in their ability to establish symbioses. We show that the coral host transcriptome remains almost unchanged during infection by competent symbionts, but is massively altered by symbionts that fail to establish symbioses. Our data suggest that successful coral-algal symbioses depend mainly on the symbionts' ability to enter the host in a stealth manner rather than a more active response from the coral host.