RUI: Evaluating how cnidarian hosts and algal endosymbionts coordinate cell divisions to maintain healthy symbiosis

负责建造热带珊瑚礁的珊瑚正在以惊人的速度消失，因为海水温度升高导致珊瑚漂白并驱逐它们所依赖的藻类共生体。没有这些共生体，珊瑚无法从阳光中获取能量，因此，它们难以在营养贫乏的热带沃茨中茁壮成长，甚至生存。为了设计解决方案来解决珊瑚礁面临的威胁，有必要了解漂白过程的细胞事件。事实上，人们对健康的珊瑚和共生体如何协调细胞分裂知之甚少，尽管藻类存在于单个珊瑚细胞中。事实上，珊瑚和藻类细胞分裂的分离与漂白有关。该建议的目标是确定什么样的作用，调节异常的藻类细胞周期中发挥漂白和评估两种机制涉及共生体细胞分裂的调节。了解这一点可以为减轻珊瑚漂白的战略提供信息。在Wofford学院，该提案将资助9个本科生研究项目，生成公开可用的测序数据，这些数据将改变生物信息学教学，并为本科生生物学课程各个层次的基于课程的本科生研究提供物质支持。参加课程研究的学生与参加传统研究项目的学生受益相似;然而，由于他们在常规学期中进行，这些课程缺乏阻止代表性不足的群体的学生参与的障碍。总的来说，所提议的活动将提高南卡罗来纳州经济最多样化的大学的50多名本科生的教育成果。（二）通过评估培养的共生体中的基因表达和膜脂组成，与共生体相比，在宿主中;以及（3）通过遗传学手段改变将共生体与宿主分离的细胞内区室的pH值，并测量pH值对藻类细胞分裂的影响。核心假设是，热应激导致宿主和共生体细胞周期的解偶联，这是通过磷酸盐交换和藻类微环境的pH值来协调的。这项工作对该领域很重要，因为要解决压力引起的漂白，必须揭示负责维持健康共生的机制。事实上，如果阐明了决定耐热性的细胞特征，就更容易预测哪些珊瑚最容易受到气候变化的影响，并将保护工作集中在这些物种上。同样，某些藻类共生体对热致漂白有抵抗力。一个被提出的解释是，耐热物种的分裂速度较慢，这使得它们不太可能在高温下过度增殖并给宿主带来负担。我们的工作将提供深入了解这一点，并可能更容易确定最好的物种，以繁殖成用于珊瑚礁恢复的幼珊瑚。这个奖项反映了NSF的法定使命，并已被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The corals responsible for building tropical reefs are disappearing at an alarming rate as elevated sea temperatures cause them to bleach and expel the algal symbionts they rely on. Without these symbionts, corals are unable to harvest energy from sunlight and, therefore, struggle to thrive or even survive in the nutrient-poor waters of the tropics. To devise solutions to address the threat to coral reefs, it is necessary to understand the cellular events underpinning the bleaching process. Indeed, little is known about how healthy corals and symbionts coordinate cell divisions even though the algae reside within individual coral cells. In fact, uncoupling of coral and algal cell divisions has been implicated in bleaching. The objectives for this proposal are to determine what role dysregulation of the algal cell cycle plays in bleaching and to assess two mechanisms implicated in regulation of symbiont cell division. Understanding this may inform strategies for mitigating coral bleaching. At Wofford College, this proposal will fund nine undergraduate research projects, generate publicly available sequencing data that will transform bioinformatics instruction, and provide material support for course-based undergraduate research at all levels of the undergraduate biology curriculum. Students who participate in course-based research benefit similarly to students who participate in traditional research programs; however, because they occur during the regular semester, these courses lack the barriers to access that prevent participation by students from underrepresented groups. Altogether, the proposed activities will enhance educational outcomes for more than 50 undergraduates at South Carolina’s most economically diverse college.The objectives for this project will be accomplished by completing three specific aims: (1) to measure the link between heat stress and increased symbiont proliferation; (2) to assess phosphate limitation as a mechanism used by hosts to regulate algal proliferation by evaluating gene expression and membrane lipid composition in cultured symbionts compared to symbionts in hosts; and (3) to pharmacologically and genetically alter the pH of the intracellular compartment separating symbionts from their hosts and measure the effect of pH on algal cell division. The central hypothesis is that heat stress causes an uncoupling of host and symbiont cell cycles, which are coordinated through phosphate exchange and the pH of the algal microenvironment. This work is important for the field because to address stress-induced bleaching, the mechanisms responsible for maintaining healthy symbiosis must be uncovered. Indeed, if the cellular traits dictating thermotolerance are elucidated, it will be easier to predict which corals are most susceptible to climate change and to focus conservation efforts on those species. Likewise, certain species of algal symbiont are resistant to heat-induced bleaching. One proposed explanation is that thermotolerant species are slower to divide, making them less likely to over-proliferate at high temperatures and burden their hosts. Our work will provide insight into this and may make it easier to determine the best species to inoculate into juvenile corals being used for reef restoration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.