Conforming corals and their cantankerous cousins

This study builds on the idea of a coral holobiont, and suggests that some species of coral may display a type of plasticity to environmental changes by modifying their microbiome; this could be beneficial to survival faced with anthropogenic pressure.

The microbiomes of two species of coral (Acropora hemprichii and Pocillopora verrucosa) were sequenced during a reciprocal transplantation experiment across 5 sites with varying levels of anthropogenic impact. P. verrucosa showed a fairly consistent microbiome, whereas A. hemprichii showed variation. This lead to the proposal of microbiome “conformers and regulators”. Conformers change their microbiome with their environment, whereas regulators maintain their microbiome regardless of their environment.

This paper concludes by suggesting conformers like A. hemprichii will be better able to cope with environmental change. Whilst it acknowledges that more research is required to confirm this, I am not convinced by this conclusions validity.

Whilst the paper mentions that A. hemprichii had more microbes associated with disease, it does not discuss how, by taking up different microbes, conformers could be increasing their risk of disease, which could negate any benefits their ability to adjust to environmental change might have. The conclusions would have been more robust if some measure of mortality of the two species was included.

Reference: Ziegler M, Grupstra C, Barreto M, Eaton M, BaOmar J, Zubier K, Al-Sofyani A, Turki A,Ormond R, Voolstra C, (2019), Coral bacterial community structure responds to environmental change in a host-specific manner, nature communications, https://doi.org/10.1038/s41467-019-10969-5