Effects of Viruses on Coral Fitness

珊瑚是重要的生态系统工程师，为热带珊瑚礁提供栖息地和养分循环。然而，由于全球工业化和人口增长的人为影响，世界范围内的珊瑚物种丰富度和丰度正在下降。在过去的几十年里，全球珊瑚覆盖面积估计下降了20%到60%，大约三分之一的已知造礁珊瑚目前面临着灭绝的危险。珊瑚疾病是热带珊瑚礁数量减少的主要原因，因此，对这些疾病的原因和补救措施进行调查至关重要。目前，人们对感染珊瑚的病毒知之甚少。这个项目将解决这个问题。已经证明，在急性应激发作后，珊瑚组织中会产生疱疹样病毒。然而，病毒多样性特征并没有告诉科学家病毒感染对珊瑚宿主的影响。该项目将调查珊瑚的病毒感染是否会导致珊瑚的疾病和/或生殖适应性降低。具体而言，该项目旨在比较和对比疾病发作期间珊瑚组织中存在的病毒的相对丰度和多样性，特别是Porites物种的生长异常和Montastraea物种的白色鼠疫病。将在健康和患病珊瑚上进行病毒DNA的焦磷酸测序，以：i)表征新的病毒类型，ii)确定病毒类型是否与特定疾病相关，以及iii)解决病毒导致珊瑚适应性降低的中心假设。珊瑚病毒组的序列分析和功能注释将确定这些病毒的系统发育和进化关系，并确定宿主感染和疾病的病毒机制。病毒在宿主适应性中的作用将通过珊瑚繁殖力、幼虫存活率和在模型珊瑚——千孔Acropora上的定居实验来进一步探讨。病毒将从成虫、卵束和幼虫中分离出来，以确定病毒感染的传播模式和个体适应度效应。这一建议将扩大珊瑚分类群、疾病、发育阶段和病毒特征的地理区域，扩大我们对这些珊瑚寄生虫多样性的一般认识。对健康和患病珊瑚中病毒联合体的检查结合病毒接种实验将采取下一步措施，并为科学家提供病毒在珊瑚礁生态系统中扮演的生态角色的线索。这种高通量测序和基于显微镜的方法的结合将使我们更全面地了解珊瑚病毒在全息生物适应性和疾病中的多样性和作用。最后，深入了解病毒如何传播将为决策者提供关于如何控制病毒爆发的更好信息，包括限制感染和疾病的传播。最近的宏基因组学工作已经开始揭示与各种生态系统相关的独特病毒组合。在很大程度上，这项工作主要集中在来自开放海洋和温带海岸的噬菌体上。该项目将使用类似的方法调查热带石珊瑚中的病毒，这是一组高度受威胁的生物，为海洋生物和当地社区提供了大量的生态系统服务。在健康、患病和不同生命阶段的珊瑚中病毒群落的特征将为科学家提供关于病毒在这些关键生态系统工程师的建立、健康和恢复能力中所起作用的线索。佛罗里达国际大学（FIU）是美国最大的少数民族和城市服务机构之一。在项目过程中，将为本科生、研究生和博士后提供指导。本项目将为海洋科学、分子生物学、发育生物学、珊瑚礁生态学和生物信息学领域的两名女研究生、一名博士后研究员和两名本科生提供动手培训资金。这种跨学科培训将有助于这些年轻科学家在海洋科学领域发展广泛和精通技术的学术生涯。最后，本项目将为年轻少数民族女性研究者的科学事业奠定坚实的基础。

Corals are important ecosystem engineers, providing habitat and nutrient recycling to tropical reefs. However, coral species richness and abundance are in decline world-wide, due in large part to anthropogenic impacts stemming from global industrialization and human population growth. Over the past several decades, global coral cover is estimated to have declined between ~20 to 60%, and approximately one-third of all known reef-building corals currently face an elevated risk of extinction. Coral disease is a major contributor to this decline of tropical reefs, and therefore, investigations into the causes of and remedies to these diseases are of critical importance. Currently little is known about viruses that infect corals. This project will address this issue.Herpes-like viruses have been shown to be produced in coral tissues after acute episodes of stress.Viral diversity characterization, however, does not inform scientists about the effects of viral infection on coral hosts. This project will investigate whether viral infection in corals leads to disease and/or reductions in coral reproductive fitness. Specifically, this project aims to compare and contrast the relative abundance and diversity of viruses present in coral tissues during episodes of diseases, particularly, growth anomalies in Porites species and white plague disease in Montastraea species. Pyrosequencing of viral DNA will be conducted on healthy and diseased corals to: i) characterize new viral types, ii) determine whether viral types are associated with particular diseases, and iii) address the central hypothesis that viruses contribute to reduced coral fitness. Sequence analysis and functional annotation of coral viromes will determine the phylogenetic and evolutionary relationships of these viruses and identify viral mechanisms of host infection and disease. The role of viruses in host fitness will be further explored using coral fecundity and larval survivorship and settlement experiments on the model coral, Acropora millepora. Viruses will be isolated from adults, egg bundles, and larvae, in order to determine the transmission mode and ontogenic fitness effects of viral infection.This proposal will expand the coral taxa, diseases, developmental stages, and geographic regions from which viruses have been characterized, broadening our general knowledge about the diversity of these coral parasites. The examination of viral consortia in healthy and diseased corals combined with viral inoculation experiments will then take the next step and provide scientists clues about the ecological roles that viruses play in coral reef ecosystems. This combination of high-throughput sequencing and microscopy-based methods will lead to a more comprehensive picture of the diversity and role(s) of coral viruses in holobiont fitness and disease. Lastly, insight into how viruses are transmitted will give policymakers better information about how to control viral outbreaks, including limiting the spread of infection and disease.Recent metagenomics work has begun to uncover unique viral assemblages associated with a variety of ecosystems. To a large extent, this work has focused on phages from the open ocean and temperate coasts. This project will use similar methods to investigate viruses in tropical stony corals, a group of highly threatened organisms which provide a multitude of ecosystem services to marine organisms and local communities. The characterization of viral consortia in healthy, diseased, and different life stages of corals will provide scientists clues about the roles that viruses play in the establishment, health, and resilience of these critical ecosystem engineers.Florida International University (FIU) is one of the largest minority and urban-serving institutions in the country. During the course of this project, mentorship will be provided to undergraduates, graduates, and postdoctoral researchers. This project will provide funds to begin the hands-on training of two female graduate students, a postdoctoral researcher, and two undergraduates in marine science, molecular biology, developmental biology, coral reef ecology, and bioinformatics. Such interdisciplinary training will help these young scientists develop a broad and technologically savvy academic career in the marine sciences. Lastly, this project will provide a solid foundation for the scientific career of a young female minority investigator.