Host–symbiont transcriptomic changes during natural bleaching and recovery in the leaf coral Pavona decussata

Yanjie ZHANG, Jack Chi Ho IP, James Y. XIE, Yip Hung YEUNG, Yanan SUN, Jian Wen QIU*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

10 Citations (Scopus)

Abstract

Coral bleaching has become a major threat to coral reefs worldwide, but for most coral species little is known about their resilience to environmental changes. We aimed to understand the gene expressional regulation underlying natural bleaching and recovery in Pavona decussata, a dominant species of scleractinian coral in the northern South China Sea. Analyzing samples collected in 2017 from the field revealed distinct zooxanthellae density, chlorophyll a concentration and transcriptomic signatures corresponding to changes in health conditions of the coral holobiont. In the host, normal-looking tissues of partially bleached colonies were frontloaded with stress responsive genes, as indicated by upregulation of immune defense, response to endoplasmic reticulum, and oxidative stress genes. Bleaching was characterized by upregulation of apoptosis-related genes which could cause a reduction in algal symbionts, and downregulation of genes involved in stress responses and metabolic processes. The transcription factors stat5b and irf1 played key roles in bleaching by regulating immune and apoptosis pathways. Recovery from bleaching was characterized by enrichment of pathways involved in mitosis, DNA replication, and recombination for tissue repairing, as well as restoration of energy and metabolism. In the symbionts, bleaching corresponded to imbalance in photosystems I and II activities which enhanced oxidative stress and limited energy production and nutrient assimilation. Overall, our study revealed distinct gene expressional profiles and regulation in the different phases of the bleaching and recovery process, and provided new insight into the molecular mechanisms underlying the holobiont's resilience that may determine the species’ fate in response to global and regional environmental changes.

Original languageEnglish
Article number150656
JournalScience of the Total Environment
Volume806
Issue numberPart 2
Early online date28 Sept 2021
DOIs
Publication statusPublished - 1 Feb 2022
Externally publishedYes

Bibliographical note

Funding Information:
This project was supported by Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) ( GML2019ZD0404 , GML2019ZD0409 ), Hong Kong Branch of South Marine Science and Engineering Guangdong Laboratory (Guangzhou) ( SMSEGL20SC01 , SMSEGL20SC02 ), General Research Fund of Hong Kong ( 12102018 ), Environment and Conservation Fund of Hong Kong ( 2017-03 ), and State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University ( SKLP_1920_P04 ).

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Coral bleaching
  • Coral health
  • Coral recovery
  • Global warming
  • Symbiosis
  • Transcription regulation

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