Project description:Reef-building corals live in a mutualistic relationship with photosynthetic algae (family Symbiodiniaceae) that usually provide the bulk of the energy required by the coral host. This relationship is very sensitive to temperature stress, with as little as 1°C increase above mean in sea surface temperatures (SSTs) often leading to the collapse of the association. The meta-stability of these associations has led to interest in the potential of more stress tolerant algae to supplement or substitute for the normal Symbiodiniaceae mutualists. In this respect, the apicomplexan-like microalga Chromera is of particular interest as it is considerably more temperature tolerant than are most members of the Symbiodiniaceae. Here we generated a de novo transcriptome for a Chromera strain isolated from a GBR coral (“GBR Chromera”) and compared to those of the reference strain of Chromera (“Sydney Chromera”), and to those of Symbiodiniaceae algae (Fugacium, Cladocopium and Breviolum), as well as the apicomplexan parasite, Plasmodium falciparum. By contrast with the Symbiodiniaceae, the two Chromera strains had a high level of sequence similarity evident by very low levels of divergence in orthologous genes. Although surveys of specific KEGG categories provided few general criteria by which true coral mutualists might be identified, they provide a molecular rationalization for the near ubiquitous association of Cladocopium strains with Indo-Pacific reef corals in general and with Acropora spp. in particular. In addition, HSP20 genes may underlie the higher thermal tolerance shown by Chromera compared to Symbiodiniaceae
2019-11-02 | GSE139820 | GEO
Project description:Acropora valida symbiotic Symbiodiniaceae
Project description:Transcriptional responses to heat stress were assayed in early life-history stages of 11 crosses between and amongst Acropora tenuis colonies originating from reefs along the Great Barrier Reef. We identified a single nucleotide polymorphism outlier (Fst=0.89) between populations in the unannotated gene Acropora25324, which exhibited constitutively higher gene expression in populations with dams originating from Curd reef, a far north, warm adapted inshore reef, suggesting an important role of this gene in adaptation to warmer environments. Further, juveniles exposed to heat and in symbiosis with heat-evolved Symbiodiniaceae displayed intermediate transcriptional responses between its progenitor taxa (Cladocopium goreaui) and the more stress tolerant Durusdinium trenchii, indicating that the development of heat tolerance acquisition is potentially a conserved evolutionary process in Symbiodiniaceae. These findings reveal the underlying mechanisms, and for the first time, their relative contribution, of coral responses to climate change and provide a foundation for optimizing conservation methods like assistant gene flow.
2022-07-08 | GSE176051 | GEO
Project description:Symbiodiniaceae communities of Acropora hyacinthus