Collaborative Research: Ontogenic change in Cnidarian-algal symbioses: A genomic and ecologic perspective

项目摘要：珊瑚（刺胞菌：刺胞菌：核胞菌）与光合鞭毛菌（肺泡藻：鞭毛菌：共生菌）之间的共生关系是珊瑚礁生态系统的基础和结构，对全球碳循环和生物地球化学循环有重要贡献。鉴于这种共生关系对珊瑚-藻类整体生物和珊瑚礁生态系统的重要性，了解这种共生关系的建立和长期维持的机制是必不可少的。该项目的总体目标是确定导致由成年寄主窝藏的共生体最终组装的机制和选择过程。这个问题将从生态学和基因组学两个角度进行探讨，其具体目的是确定(1)当成虫进入成熟的共生关系时，不同的共生菌株是否会对珊瑚的适合度产生不同的影响(2)共生体之间的竞争或环境条件是否有助于最终的宿主-共生体配对，以及(3)当宿主内的共生体群落被筛选到成年宿主中发现的最终组合时，宿主/共生体转录组如何变化。直接影响珊瑚适应性的特征（即生长、生存、能量生产）将在不同的环境条件下通过实验感染不同类型共生菌的珊瑚新生个体发育进行测量。同时，高通量基因表达谱将用于跟踪宿主和共生体之间基因表达的变化。总之，这些数据将用于验证或证伪假设，即在成年寄主中发现的最终共生体组合是由(a)寄主选择(b)共生体之间的竞争和/或(c)环境条件决定的。这项研究汇集了两个专注于共生关系这些方面的实验室的专业知识。科夫罗斯实验室在共生的早期个体发生和共生多样性研究方面处于领先地位，并将继续在生态学研究中处于领先地位。麦地那实验室在开发和利用基因组技术研究共生关系建立和分解过程中的转录组变化方面处于领先地位。此外，麦地那实验室有珊瑚微阵列将用于这项研究，2009年还将根据454 EST数据为两种共生菌提供寡核苷酸阵列。虽然有几个研究小组对宿主转录组进行了初步研究，但没有一个研究小组将一种方法结合起来，在一次实验中检查宿主和共生体。这将是一种强有力的方法，因为它将使研究人员能够追踪宿主和共生体之间基因表达的互补变化，并将这些变化与共生体群落中最终共生体补体建立时的更替联系起来。本研究得到的数据将为我们理解珊瑚-共生菌共生关系的建立和维持填补一个重要的空白。了解调节共生关系建立的机制将拓宽我们的知识，并有助于预测这种共生关系对未来气候条件的反应。与过去一样，基因组工具（阵列、ESTs）将通过阵列的成本分配、微阵列分析培训或序列数据随时提供给研究人员，为继续探索这些系统提供宝贵的资源。科夫罗斯将与尼亚加拉水族馆合作，制定教育和推广计划，向当地教师和公众培训和传播有关珊瑚礁的信息。麦地那实验室将继续与加州大学默塞德分校的本科生一起用多种语言（英语、西班牙语和苗语）制作科学和环境播客，并将继续与加州科学院（CAS）合作开展珊瑚礁推广工作。此外，这项工作将导致培养和指导一名博士后，至少一名研究生和至少两名本科生。通过这个项目，这些学生将有机会参与实验室和实地的研究，学习一系列的生态、分子和藻类培养技术。布法罗大学广泛的文化收藏是全世界研究人员可以使用的重要资源，拟议的资金将有助于维护。我们的EST注释可以通过我们的EST数据库（http://sequoia.ucmerced.edu/SymBioSys/）公开获得。

PROJECT SUMMARYThe symbiosis between corals (Cnidaria:Hexacorallia:Scleractinia) and photosynthetic dinoflagellate symbionts (Alveolata: Dinophycea: Symbiodinium) provides the foundation and structure of the coral reef ecosystem, as well as significant contributions to global carbon and biogeochemical cycles. Given the importance of this symbiosis to the coral-algal holobiont and the reef ecosystem, understanding the mechanisms governing the establishment and long term maintenance of this symbiosis is essential. The overall aim of this project is to identify the mechanisms and selective processes that lead to thefinal assemblage of symbionts harbored by adult hosts. This question will be approached from two perspectives, ecologic and genomic, with the specific aims of determining (1) if different Symbiodinium strains differentially affect fitness of corals as the adult settles into a mature symbiosis (2) if competition among symbionts or environmental conditions contribute to the final host-symbiont pairing and (3) how host/symbiont transcriptomes varying as the symbiont community within a host is winnowed to the final assemblage found in the adult host. Traits that directly affect coral fitness (i.e. growth, survivorship, energy production) will be measured under different environmental conditions over the ontogeny of coral recruits that are experimentally infected with different types of Symbiodinium. Concurrently, high throughput gene expression profiling will be used to follow changes in gene expression between host and symbiont. Together, these data will be used to validate or falsify the hypotheses that the final symbiont assemblage found in the adult host is determined by (a) host selection (b) competition among symbionts and/or (c) environmental condition.This study pools the expertise of two labs that have focused on these aspects of the symbiosis. The Coffroth lab pioneered the studies on early ontogeny of the symbiosis and symbiont diversity and will continue to take the lead in the ecological studies. The Medina lab is at the forefront in the development and utilization of genomic technology to study transcriptomic changes during the establishment and breakdown of the symbiosis. Furthermore, the Medina lab has the coral microarrays to be used in this study and in 2009 will also have oligo arrays for two Symbiodinium species based on 454 EST data. Although several groups have initial studies of the host transcriptome, none have combined an approach that examines the host and the symbiont in a single experiment. This will be a powerful approach as it will allow the investigators to track complementary changes in gene expression between host and symbiont and relate those to turnover in the symbiont community as the final symbiont complement is established.The data resulting form the study will bridge an important gap in our understanding of the establishment and maintenance of coral-Symbiodinium symbiosis. Understanding the mechanism(s) regulating the establishment of the symbiosis will broaden our knowledge and help to predict the response of this symbiosis to future climate conditions. As in the past, the genomic tools (arrays, ESTs) will be made readily available to researchers via array distribution at cost, microarray analysis training, or sequence data, providing valuable resources to continue exploring these systems.In conjunction the Aquarium of Niagara, Coffroth will develop educational and outreach programs to train and disseminate information on coral reefs to local area teachers and the general public. The Medina lab will continue to produce science and environment podcasts in multiple languages (English, Spanish and Hmong) with undergraduate students at UC Merced and will continue to collaborate with the California Academy of Sciences (CAS) in their coral reef outreach efforts. Additionally, this work will result in the training and mentoring of a postdoctoral fellow, at least one graduate student and at least 2 undergraduates. Through this project these students will have the opportunity to participate in research in both a lab and field setting, learning a range of ecological, molecular and algal culturing techniques. The extensive culture collection housed at the University at Buffalo is an important resource that is available to researchers worldwide which the proposed funding will help to maintain. Our EST annotations are publicly available through our EST database (http://sequoia.ucmerced.edu/SymBioSys/).