2025-08-21 東京大学,東京海洋大学
大潮で水面から露出したサンゴが大量に粘液を放出している様子
<関連情報>
- https://www.aori.u-tokyo.ac.jp/research/news/2025/20250821-1.html
- https://www.aori.u-tokyo.ac.jp/research/news/2025/files/20250821_summary_1.pdf
- https://www.cell.com/iscience/fulltext/S2589-0042(25)01547-0
全球的な海洋病原体ビブリオ・コラリリティカスに対する殺菌活性を有するサンゴ由来ペプチド A coral peptide with bactericidal activity against a global marine pathogen, Vibrio coralliilyticus
Kako Aoyama ∙ Masahiko Okai ∙ Nobuhiro Ogawa ∙ … ∙ Masami Ishida ∙ Koji Inoue ∙ Toshiyuki Takagi
iScience Published:August 20, 2025
DOI:https://doi.org/10.1016/j.isci.2025.113286
Highlights
- A coral peptide, digitiferin, kills pathogenic bacteria that threaten reef health globally
- Corals secrete digitiferin into mucus to block invading pathogens at the epithelial surface
- Digitiferin is active against Vibrio coralliilyticus under low-salt conditions in the mucus
- Salt sensitivity may explain why other coral AMPs are ineffective against Vibrio pathogens
Summary
Rising seawater temperatures weaken coral immunity and increase the virulence of the coral pathogen Vibrio coralliilyticus. Here, we identified digitiferin, an antimicrobial peptide (AMP), in the coral, Acropora digitifera. Recombinant digitiferin showed antibacterial activity against both Gram-positive and -negative bacteria. A 3D structural model and microscopic observations revealed that digitiferin damages bacterial surfaces. However, initial growth inhibition tests in 1.5% (w/v) NaCl showed no effect on pathogens. We found that digitiferin is secreted into mucus, where NaCl concentrations are lower than in seawater. Hence, we hypothesized that it is active against pathogens in low-salt environments. By re-evaluating under low-salt conditions, we discovered that digitiferin kills Vibrio species. Digitiferin homologs were found in multiple coral species, suggesting that digitiferin may serve as a first-line defense mechanism and determine disease susceptibility in corals. These findings enhance our understanding of coral-pathogen interactions and will facilitate the development of techniques to overcome Vibrio disease.
