TY - JOUR

T1 - Hypoxia as a physiological cue and pathological stress for coral larvae

AU - Alderdice, Rachel

AU - Pernice, Mathieu

AU - Cárdenas, Anny

AU - Hughes, David J.

AU - Harrison, Peter L.

AU - Boulotte, Nadine

AU - Chartrand, Katie

AU - Kühl, Michael

AU - Suggett, David J.

AU - Voolstra, Christian R.

N1 - Publisher Copyright: © 2021 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.

PY - 2022

Y1 - 2022

N2 - Ocean deoxygenation events are intensifying worldwide and can rapidly drive adult corals into a state of metabolic crisis and bleaching-induced mortality, but whether coral larvae are subject to similar stress remains untested. We experimentally exposed apo-symbiotic coral larvae of Acropora selago to deoxygenation stress with subsequent reoxygenation aligned to their night-day light cycle, and followed their gene expression using RNA-Seq. After 12 h of deoxygenation stress (~2 mg O2/L), coral planulae demonstrated a low expression of HIF-targeted hypoxia response genes concomitant with a significantly high expression of PHD2 (a promoter of HIFα proteasomal degradation), similar to corresponding adult corals. Despite exhibiting a consistent swimming phenotype compared to control samples, the differential gene expression observed in planulae exposed to deoxygenation-reoxygenation suggests a disruption of pathways involved in developmental regulation, mitochondrial activity, lipid metabolism, and O2-sensitive epigenetic regulators. Importantly, we found that treated larvae exhibited a disruption in the expression of conserved HIF-targeted developmental regulators, for example, Homeobox (HOX) genes, corroborating how changes in external oxygen levels can affect animal development. We discuss how the observed deoxygenation responses may be indicative of a possible acclimation response or alternatively may imply negative latent impacts for coral larval fitness.

AB - Ocean deoxygenation events are intensifying worldwide and can rapidly drive adult corals into a state of metabolic crisis and bleaching-induced mortality, but whether coral larvae are subject to similar stress remains untested. We experimentally exposed apo-symbiotic coral larvae of Acropora selago to deoxygenation stress with subsequent reoxygenation aligned to their night-day light cycle, and followed their gene expression using RNA-Seq. After 12 h of deoxygenation stress (~2 mg O2/L), coral planulae demonstrated a low expression of HIF-targeted hypoxia response genes concomitant with a significantly high expression of PHD2 (a promoter of HIFα proteasomal degradation), similar to corresponding adult corals. Despite exhibiting a consistent swimming phenotype compared to control samples, the differential gene expression observed in planulae exposed to deoxygenation-reoxygenation suggests a disruption of pathways involved in developmental regulation, mitochondrial activity, lipid metabolism, and O2-sensitive epigenetic regulators. Importantly, we found that treated larvae exhibited a disruption in the expression of conserved HIF-targeted developmental regulators, for example, Homeobox (HOX) genes, corroborating how changes in external oxygen levels can affect animal development. We discuss how the observed deoxygenation responses may be indicative of a possible acclimation response or alternatively may imply negative latent impacts for coral larval fitness.

KW - coral

KW - development

KW - gene expression profiling

KW - hypoxia

KW - RNA-Seq

U2 - 10.1111/mec.16259

DO - 10.1111/mec.16259

M3 - Journal article

C2 - 34716959

AN - SCOPUS:85119261632

VL - 31

SP - 571

EP - 587

JO - Molecular Ecology

JF - Molecular Ecology

SN - 0962-1083

IS - 2

ER -