Polyamine impact on physiology of early stages of reef-building corals-insights from rearing experiments and RNA-Seq analysis.

Polyamines are involved in various functions related to the cellular-level responses. To assess effects of polyamines on marine organisms, rearing experiments and comprehensive gene expression analyses were conducted on Acropora digitifera and Acropora sp.1, representative reef-building corals along the west-central coast of Okinawa, Japan, to evaluate effects of putrescine. Concentrations of putrescine ≥ 1 mM dissolved tissues of juvenile polyps and increased mortality of planula larvae. RNA-Seq analysis of juvenile polyps exposed to putrescine at the stage before effects became visible revealed dynamic fluctuations in gene expression in the putrescine-treated samples, with increased expression of stress-responsive genes (e.g. NAD-dependent protein deacylase sirtuin-6) and the polyamine transporter Slc18b1-like protein. These results also suggest that putrescine affects expression of genes related to ribosomes and translation. This study provides important insights into roles of polyamines and future directions regarding physiological responses of corals.