Red fluorescence in coral larvae is associated with a diapause‐like state

Abstract

Effective dispersal across environmental gradients is the key to species resilience to environmental perturbation, including climate change. Coral reefs are among the most sensitive ecosystems to global warming, but factors predicting coral dispersal potential remain unknown. In a reef-building coral Acropora millepora, larval fluorescence emerged as a possible indicator of dispersal potential since it correlates with responsiveness to a settlement cue. Here, we show that gene expression in red fluorescent larvae of A. millepora is correlated with diapause-like characteristics highly likely to be associated with extended dispersal. We compared gene expression among three larval fluorescent morphs under three coloured light treatments. While colour morphs did not differ in their gene expression responses to light colour, red larvae demonstrated gene expression signatures of cell cycle arrest and decreased transcription accompanied by elevated ribosome production and heightened defenses against oxidative stress. A meta-analysis revealed that this profile was highly similar to the signatures of elevated thermal tolerance in the same coral species, and moreover, functionally resembled diapause states in an insect and a nematode. Our results support a connection between red fluorescence and long-range dispersal, which offers a new perspective on the molecular underpinnings of coral larval dispersal and the biological function of GFP-like fluorescent proteins.

Acropora digitiferaEncodes the Largest Known Family of Fluorescent Proteins that Has Persisted during the Evolution ofAcroporaSpecies

“…2009; Roth and Deheyn 2013) and possible roles in larval settlement behavior and long-range dispersal in larvae (Kenkel et al. 2011; Strader et al. 2016).…”

Representative diatom and coccolithophore species exhibit divergent responses throughout simulated upwelling cycles

“…Gene Expression Analysis. RNA libraries for the UCBC simulations were constructed using a custom protocol for 3' poly-A-directed mRNA-seq (also known as TagSeq) based on Meyer et al (27) and adapted for Illumina HiSeq based on Lohman et al (28) and Strader et al (29) (Supplementary Materials and Methods). PCR duplicates were removed based on a matching degenerate leader sequence incorporated during cDNA synthesis and a match of the first 20 bases as described by Dixon et al (30).…”

Peer Review #1 of "Relationship between Acropora millepora juvenile fluorescence and composition of newly established Symbiodinium assemblage (v0.1)"

“…Furthermore, while some species of dinoflagellates move in response to light (Cullen, 1985;Horiguchi et al, 1999), it is unclear whether Symbiodinium are able to detect and move toward particular wavelengths emitted by coral juveniles. For example, using differential juvenile fluorescent intensities, signals and patterns for inter/intra-specific communication similar to what has been suggested for corals and reef fish (Matz, Marshall & Vorobyev, 2006;Lagorio, Cordon & Iriel, 2015) Manuscript to be reviewed to the onset of symbiosis (Leutenegger et al, 2007;Roth et al, 2007;Kenkel et al, 2011;Roth, Fan & Deheyn, 2013;Strader, Aglyamova & Matz, 2016). It is currently unclear if corals use variable fluorescence signals that could, for example, allow for the attraction of commensal bacteria or their dinoflagellate symbionts, Symbiodinium.…”