First characterization of bacterial pathogen, Vibrio alginolyticus, for Porites andrewsi White syndrome in the South China Sea

PLoS One. 2013 Sep 24;8(9):e75425. doi: 10.1371/journal.pone.0075425. eCollection 2013.

Abstract

Background: White syndrome, a term for scleractinian coral disease with progressive tissue loss, is known to cause depressed growth and increased morality of coral reefs in the major oceans around the world, and the occurrence of this disease has been frequently reported in the past few decades. Investigations during April to September in both 2010 and 2011 identified widespread Porites andrewsi White syndrome (PAWS) in Xisha Archipelago, South China Sea. However, the causes and etiology of PAWS have been unknown.

Methodology/principal findings: A transmission experiment was performed on P. andrewsi in the Qilianyu Subgroup (QLY). The results showed that there was a significant (P ≤ 0.05) difference between test and control groups after 28 days if the invalid replicates were excluded. Rates of tissue loss ranged from 0.90-10.76 cm(2) d(-1) with a mean of 5.40 ± 3.34 cm(2) d(-1) (mean ± SD). Bacterial strains were isolated from the PAWS corals at the disease outbreak sites in QLY of the Xisha Archipelago, South China Sea, and included in laboratory-based infection trials to satisfy Koch's postulates for establishing causality. Following exposure to bacterial concentrations of 10(5) cells mL(-1), the infected colonies exhibited similar signs to those observed in the field. Using phylogenetic 16S rRNA gene analysis, classical phenotypic trait comparison, Biolog automatic identification system, MALDI-TOF mass spectrometry and MALDI Biotyper method, two pathogenic strains were identified as Vibrio alginolyticus .

Conclusion/significance: This is the first report of V. alginolyticus as a pathogenic agent of PAWS in the South China Sea. Our results point out an urgent need to develop sensitive detection methods for V. alginolyticus virulence strains and robust diagnostics for coral disease caused by this and Vibrio pathogenic bacterium in the South China Sea.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthozoa / microbiology*
  • Base Sequence
  • China
  • DNA Primers / genetics
  • Disease Transmission, Infectious
  • Molecular Sequence Data
  • Oceans and Seas
  • Phylogeny*
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Vibrio alginolyticus / classification
  • Vibrio alginolyticus / genetics*
  • Vibrio alginolyticus / pathogenicity*
  • Virulence

Substances

  • DNA Primers
  • RNA, Ribosomal, 16S

Grants and funding

This work was supported by grants from the National Science and Technology Support Program (no. 2009BAB44B02); the National Natural Science Foundations of China (no. 41066003, no. 31060360 and no. 30760190); and the Project of Fok Ying Tong Education Foundation (no. 121030). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.