1] Department of Microbiology, Oregon State University, Corvallis, OR, USA [2] Department of Biological Sciences, Florida International University, North Miami, FL, USA.
Center for Marine and Environmental Studies, University of the Virgin Islands, St Thomas, Virgin Islands, USA.
ISME J. 2014 Feb;8(2):271-83. doi: 10.1038/ismej.2013.137. Epub 2013 Aug 15.
White plague (WP)-like diseases of tropical corals are implicated in reef decline worldwide, although their etiological cause is generally unknown. Studies thus far have focused on bacterial or eukaryotic pathogens as the source of these diseases; no studies have examined the role of viruses. Using a combination of transmission electron microscopy (TEM) and 454 pyrosequencing, we compared 24 viral metagenomes generated from Montastraea annularis corals showing signs of WP-like disease and/or bleaching, control conspecific corals, and adjacent seawater. TEM was used for visual inspection of diseased coral tissue. No bacteria were visually identified within diseased coral tissues, but viral particles and sequence similarities to eukaryotic circular Rep-encoding single-stranded DNA viruses and their associated satellites (SCSDVs) were abundant in WP diseased tissues. In contrast, sequence similarities to SCSDVs were not found in any healthy coral tissues, suggesting SCSDVs might have a role in WP disease. Furthermore, Herpesviridae gene signatures dominated healthy tissues, corroborating reports that herpes-like viruses infect all corals. Nucleocytoplasmic large DNA virus (NCLDV) sequences, similar to those recently identified in cultures of Symbiodinium (the algal symbionts of corals), were most common in bleached corals. This finding further implicates that these NCLDV viruses may have a role in bleaching, as suggested in previous studies. This study determined that a specific group of viruses is associated with diseased Caribbean corals and highlights the potential for viral disease in regional coral reef decline.
热带珊瑚的“白色瘟疫”样疾病与世界范围内的珊瑚礁衰退有关，尽管其病因通常未知。迄今为止的研究集中在细菌或真核病原体作为这些疾病的来源；没有研究检查病毒的作用。本研究采用透射电子显微镜（TEM）和 454 焦磷酸测序相结合的方法，比较了 24 个来自表现出“白色瘟疫”样疾病和/或白化症状的 Montastraea annularis 珊瑚以及对照同种类珊瑚和相邻海水的病毒宏基因组。TEM 用于观察患病珊瑚组织。患病珊瑚组织中未肉眼观察到细菌，但病毒颗粒和与真核环状 Rep 编码单链 DNA 病毒及其相关卫星（SCSDVs）的序列相似性在 WP 患病组织中丰富存在。相比之下，任何健康珊瑚组织中都未发现与 SCSDVs 的序列相似性，表明 SCSDVs 可能在 WP 疾病中发挥作用。此外，疱疹病毒科基因特征主导健康组织，这与疱疹样病毒感染所有珊瑚的报道相符。核质大 DNA 病毒（NCLDV）序列与最近在 Symbiodinium（珊瑚的藻类共生体）培养物中鉴定出的序列相似，在白化珊瑚中最为常见。这一发现进一步表明，这些 NCLDV 病毒可能在之前的研究中提示的白化过程中发挥作用。本研究确定了一组特定的病毒与患病加勒比珊瑚有关，并强调了病毒疾病在区域珊瑚礁衰退中的潜在作用。
