EAGER: Development of a Model System for Study of Dinoflagellate-Cnidarian Symbiosis

在美国和世界各地，珊瑚礁对生物多样性保护、海岸线保护、食品生产、药物发现和娱乐具有巨大的生态和经济重要性。 不幸的是，珊瑚礁近年来出现了广泛的和日益严重的退化，这显然主要是由于珊瑚无法在海洋温度、酸度和污染增加所造成的压力下生存。 珊瑚死亡之前通常会发生“漂白”，即珊瑚动物失去通常生活在其细胞内的共生藻类，并通过光合作用为它们提供大部分（通常90%）的能量。 最近，海洋和养护生物学家对这一问题给予了很大关注，但由于缺乏有关珊瑚生长的分子和细胞机制以及动物宿主与藻类共生体之间相互作用的基本信息，他们的努力受到严重阻碍。 这一差距在很大程度上是由于珊瑚本身对实验室研究造成了许多重大困难。 在生物学和生物医学研究的其他领域，取得的进展主要来自对少数“模式生物”的深入研究，选择这些生物不是因为它们的内在利益，而是因为它们对深入实验研究的敏感性，包括应用强大的遗传方法研究细胞功能。 该项目的重点是开发小海葵Aiptasia作为珊瑚分子和细胞生物学研究的模型系统。 Aiptasia与珊瑚关系密切，与相似或相同类型的藻类共生，但它具有许多巨大的实验优势。 这里提出的具体研究建立在PI实验室的最新进展基础上（特别是在实验室中诱导产卵和产生幼虫），并集中于为该系统开发遗传方法的三个不同方面，即（1）在遗传杂交中跟踪自然和诱导变异的方法，（2）获得RNA介导的基因表达敲低的方法，和（3）用允许破坏或标记单个基因的DNA构建体转化动物的方法。这些方法的进展应会对基本珊瑚生物学的调查产生重大影响，并将通过在会议上的介绍、出版物以及实验室专用网站和社区维护的网站向研究界通报。 在这个过程中，博士后和博士前学生将接受多样化和复杂的培训，为他们在研究和/或政策方面的独立职业做好准备。 此外，复杂和美丽的珊瑚礁生态系统的内在魅力将提供许多机会，就珊瑚特有的和更普遍的基础科学问题及其与养护的关系，向年轻学生和公众进行有效的宣传。

In the U.S. and around the world, coral reefs are of enormous ecological and economic importance for biodiversity preservation, shoreline protection, food production, drug discovery, and recreation. Unfortunately, coral reefs have shown extensive and increasing degradation in recent years, apparently due largely to the inability of the corals to survive the stresses imposed by increasing ocean temperature, acidity, and pollution. Coral death is typically preceded by "bleaching", in which the coral animals lose the symbiotic algae that normally live inside their cells and provide them with most (often 90%) of their energy through photosynthesis. There has been much recent attention to this problem from marine and conservation biologists, but their efforts have been severely handicapped by the lack of basic information about the molecular and cellular mechanisms that underlie coral growth and the interactions between the animal hosts and their algal symbionts. This gap is due largely to the fact that corals themselves present multiple significant difficulties for laboratory study. In other areas of biological and biomedical research, progress has come primarily from intensive studies of a small number of "model organisms" that were chosen not for their intrinsic interest, but instead for their susceptibility to intensive experimental investigation, including the application of powerful genetic methods for investigation of cell function. This project focuses on developing the small sea anemone Aiptasia as a model system for the study of coral molecular and cell biology. Aiptasia is closely related to corals and is symbiotic with similar or identical types of algae, but it has many great experimental advantages. The specific studies proposed here build on recent progress in the PI's laboratory (notably the induction of spawning and production of larvae in the laboratory) and focus on three different aspects of developing genetic methods for this system, namely (1) methods for following natural and induced variation in genetic crosses, (2) methods for obtaining RNA-mediated knockdown of gene expression, and (3) methods for transforming animals with DNA constructs that will allow disruption or tagging of individual genes. Progress with these methods should have a major impact on investigations of basic coral biology and will be communicated to the research community through presentations at conferences, publications, and both laboratory-specific and community-maintained websites. In the process, both postdoctoral and predoctoral students will receive a diverse and sophisticated training to prepare them for independent careers in research and/or policy. In addition, the intrinsic fascination of the complex and beautiful coral-reef ecosystem will provide numerous opportunities for effective outreach to both younger students and the general public on both coral-specific and more general issues of basic science and its relationship to conservation.