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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Aquatic Physiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1339907
This article is part of the Research Topic The Cellular Stress Response and Physiological Adaptations of Corals Subjected to Environmental Stressors and Pollutants, Volume II View all 7 articles

Coexistence of nonfluorescent chromoproteins and fluorescent proteins in massive Porites spp. corals manifesting a pink pigmentation response

Provisionally accepted
Toshiyuki SUZUKI Toshiyuki SUZUKI 1*Beatriz CASARETO Beatriz CASARETO 1Mathinee YUCHAROEN Mathinee YUCHAROEN 2Hideo DOHRA Hideo DOHRA 3Yoshimi SUZUKI Yoshimi SUZUKI 1
  • 1 Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan
  • 2 Marine and Coastal Resources Institute, Hat Yai Campus, Prince of Songkla University, Songkhla, Thailand
  • 3 Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Shizuoka, Japan

The final, formatted version of the article will be published soon.

    Introduction: Several fluorescent proteins (FPs) and chromoproteins (CPs) are present in anthozoans and play possible roles in photoprotection. Coral tissues in massive corals often display discoloration accompanied by inflammation. Incidences of the pink pigmentation response (PPR) in massive Porites, described as inflammatory pink lesions of different shapes and sizes, has recently increased worldwide. FPs are reported to be present in PPR lesions, wherein a red fluorescent protein (RFP) appears to play a role in reducing reactive oxygen species. However, to date, the biochemical characterization and possible roles of the pigments involved are poorly understood. The present study aimed to identify and characterize the proteins responsible for pink discoloration in massive Porites colonies displaying PPRs, as well as to assess the differential distribution of pigments and the antioxidant properties of pigmented areas.Method: CPs were extracted from PPR lesions using gel-filtration chromatography and identified via genetic analysis using liquid chromatography-tandem mass spectrometry. The coexistence of CPs and RFP in coral tissues was assessed using microscopic observation.Photosynthetic antivity and hydrogen peroxide-scavenging activitiy were measured to assess coral stress conditions.Results: The present study revealed that the same CP (plut2.m8.16902.m1) isolated from massive Porites was present in both the pink spot and patch morphologies of the PPR. CPs were also found to coexist with RFP in coral tissues that manifested a PPR, with a differential distribution (coenosarc or tip of polyps' tentacles). High hydrogen peroxide-scavenging rates was found in tissues affected by PPR.Discussion and Conclusions: The coexistence of CPs and RFP suggests their possible differential role in coral immunity. CPs, which are specifically expressed in PPR lesions, may serve as an antioxidant in the affected coral tissue. Overall, this study provides new knowledge to our understanding of the role of CPs in coral immunity.

    Keywords: Chromoprotein, Fluorescent protein, non-fluorescent chromoprotein, Porites spp., Oxidative Stress, pink pigmentation response, innate immune response

    Received: 17 Nov 2023; Accepted: 16 Apr 2024.

    Copyright: © 2024 SUZUKI, CASARETO, YUCHAROEN, DOHRA and SUZUKI. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Toshiyuki SUZUKI, Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan

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