[Coral-List] new paper published at ISME Journal "Deciphering the nature of the coral-Chromera association"

[Amin.Esmail at csiro.au]

Dear colleagues



On behalf of the co-authors, I'd like to share our recent paper published yesterday at the ISME Journal with open access.


"Deciphering the nature of the coral-Chromera association" by Amin R Mohamed, Vivian R Cumbo, Saki Harii, Chuya Shinzato, Cheong Xin Chan, Mark A Ragan, Nori Satoh, Eldon E Ball & David J Miller


Paper link: https://www.nature.com/articles/s41396-017-0005-9


Chromera is a morphologically similar alga to Symbiodinium, but more stress-tolerant. It was first discovered in corals from Sydney Harbour in 2008, and has subsequently been found in association with a variety of corals from all around the world, including the Great Barrier Reef. Chromera is fundamentally interesting because it intermediates between free-living, photosynthetic algae such as Symbiodinium, and parasites such as Plasmodium (the malaria parasite). Technically, Chromera is the closest known photosynthetic relative of the apicomplexan parasites. This evolutionary position led to the nature of the Chromera - coral relationship being questioned - is it mutualistic, in which both participants benefit, or is it a parasitic relationship?


We profiled transcriptome-wide gene expression in larvae of Acropora digitifera 4-, 12- and 48 h following exposure to Chromera. To study the nature of the interaction between corals and Chromera, the coral transcriptomic responses to Chromera were investigated and compared to the responses of the same coral host during exposure to competent strain of Symbiodinium.


The transcriptomic response of the coral to Chromera was complex and implies that host immunity is strongly suppressed, and both phagosome maturation and the apoptotic machinery is modified. These responses differ markedly from those described for infection with a competent strain of the coral mutualist Symbiodinium, instead resembling those of vertebrate hosts to parasites and/or pathogens such as Mycobacterium tuberculosis. Consistent with ecological studies suggesting that the association may be accidental, the transcriptional response of A. digitifera larvae leads us to conclude that Chromera could be a coral parasite, commensal, or accidental bystander, but certainly not a beneficial mutualist.



Please contact us with any comments and/or questions.


Best regards

Amin


Dr Amin Mohamed

OCE Postdoctoral Fellow
Aquaculture genetics and phenomics
CSIRO Agriculture and Food

Queensland Bioscience Precinct, 306 Carmody Road, St Lucia Brisbane 4067 Qld, Australia
P +61 7 3214 2563 E amin.esmail at csiro.au
www.csiro.au<http://www.csiro.au/>; http://www.csiro.au/en/Research/AF