White Syndrome Coral pathogens in the Indo-Pacific

Bacterial isolates were obtained from corals displaying White Syndrome disease signs at 3 sites: Nikko Bay in the Republic of Palau, Nelly Bay in the central Great Barrier Reef and Majuro Atoll in the Republic of the Marshall Islands.Bacterial isolates were obtained from corals displaying disease signs at three WS outbreak sites: Nikko Bay in the Republic of Palau, Nelly Bay in the central Great Barrier Reef (GBR) and Majuro Atoll in the Republic of the Marshall Islands, and used in laboratory-based infection trials to satisfy Henle-Koch's postulates, Evan's rules and Hill's criteria for establishing causality. Infected colonies produced similar signs to those observed in the field following exposure to bacterial concentrations of 1 x106 cells ml-1. Phylogenetic 16S rRNA gene analysis demonstrated that all six pathogens identified in this study were members of the g-Proteobacteria family Vibrionacae, each with greater than 98% sequence identity with the previously characterized coral bleaching pathogen Vibrio coralliilyticus. Screening for proteolytic activity of more than 150 coral derived bacterial isolates by a chemical assay and specific primers for a Vibrio family zinc-metalloprotease demonstrated a significant association between the presence of isolates capable of proteolytic activity and observed disease signs. Laboratory-based infection trials to establish causality of White Syndrome affecting corals of the Indo-Pacific. The first study to provide evidence for the involvement of a unique taxonomic group of bacterial pathogens in the aetiology of Indo-Pacific coral diseases affecting multiple coral species at multiple locations.Bulk of data is held with JCU PhD stduent Meir Sussman as part of an AIMS/JCU collaborative supervised Project.Meir Sussman was funded on an IPRS scholarship.

本研究的细菌分离株采自三处出现白色综合征（White Syndrome，WS）病症的珊瑚采样位点：帕劳共和国的尼克湾、大堡礁（Great Barrier Reef，GBR）中部的内利湾，以及马绍尔群岛共和国的马朱罗环礁。上述分离株被用于实验室感染试验，以满足科赫-亨勒法则（Henle-Koch's postulates）、埃文斯规则（Evan's rules）及希尔准则（Hill's criteria）中确立因果关系的要求。当感染菌浓度达到1×10⁶ cells·ml⁻¹时，感染的珊瑚群落会表现出与野外观测到的病症高度相似的症状。系统发育16S rRNA基因分析显示，本研究鉴定出的6株病原菌均隶属于γ-变形菌纲（g-Proteobacteria）弧菌科（Vibrionacae），且所有菌株与已表征的珊瑚白化病原菌溶珊瑚弧菌（Vibrio coralliilyticus）的序列同一性均高于98%。研究团队通过化学检测法及针对弧菌科锌金属蛋白酶的特异性引物，对150余株珊瑚来源细菌分离株的蛋白水解活性进行筛选，结果显示具备蛋白水解活性的分离株与观测到的病症之间存在显著关联。本研究通过实验室感染试验确立了印度-太平洋区域珊瑚白色综合征的致病因果关系，亦是首个为一类独特分类群的细菌病原菌参与印度-太平洋多地点、多珊瑚物种感染的珊瑚病病原学过程提供直接证据的研究。本数据集的大部分数据由詹姆斯库克大学（James Cook University，JCU）博士生迈尔·萨斯曼（Meir Sussman）持有，其属于澳大利亚海洋科学研究所（Australian Institute of Marine Science，AIMS）与JCU合作监管的研究项目的一部分。迈尔·萨斯曼获得了国际研究生研究奖学金（International Postgraduate Research Scholarship，IPRS）的资助。