EAGER: Cell to cell communication in marine phytoplankton: population density dependent control of cellular processes

EAGER：海洋浮游植物中的细胞间通讯：细胞过程的种群密度依赖性控制

• 批准号: 1140042
• 负责人: Maria Vernet
• 金额: $ 28.61万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1140042&HistoricalAwards=false
• 关键词: EAGER; Cell; cell; communication; marine

Recent discoveries have shown that cell-cell communication extends from the intra-species to the inter-kingdom level and play pivotal roles in population-wide biological events such as changes in morphology, metabolic state and population structure. Quorum sensing (QS) is a communication process that allows single cells to cooperatively function as a decentralized network. Studies in prokaryotes and, more recently, fungi have demonstrated that QS regulates the timing of key biological processes such as colony formation, sporulation, morphological changes, pathogenicity and sexual reproduction. In the marine environment, QS has been demonstrated in bacteria however, this level of mutual cooperation has not been considered for phytoplankton populations. In view of the emerging literature on the critical role of cell-cell communication, it is timely to reconsider how we regard marine phytoplankton.Thus far marine phytoplankton cell-cell interaction studies have primarily focused on chemical signals for competition against other species (e.g. allelopathy), predation deterrence and warning systems for environmental stress. There are several lines of circumstantial evidence to support QS in phytoplankton such as the timing of cell division, density dependent allelopathy and programmed cell death. However, to our knowledge there has been no direct experimentation to determine if phytoplankton can function in a cooperative consortium. Do they have a quorum sensing- type of communication to regulate intra-species processes as well as modulates inter-species interactions? Are recurrent phytoplankton communities established because these species are able to communicate with each member serving a specific role to maintain the population? These are difficult questions to address but have far reaching implications in our understanding of phytoplankton ecology.This project will test whether phytoplankton have a QS system by examining the process of autoinduction (a basic tenant for QS) for specific biological events. The PIs will test this by examining two specific areas using phytoplankton ecological and physiological measurements coupled with state of the art bio-informatic and genomic tools:I. Perform an extensive search for candidate phytoplankton QS-related genes in existing genomic and gene expression databases, based on homology with QS-related genes from other organisms. The PIs will conduct a detailed analysis to definitively map homologs of these QS regulatory pathways in their entirety as well as the few known biosynthetic pathways of QS compounds and transcriptional/translational regulators onto phytoplankton genomes. The results will be included as part of a comparative genomics study on cell-to-cell communication in phytoplankton, and the possible role of any candidate genes in QS will be tested by the experiments detailed below (2).II. Establish autoinduction of cellular processes in a diatom species using an experimental approach. The PIs will focus on the autoinduction of growth, cell morphology, allelopathy and biofilm formation using axenic cultures using two model diatom species, Phaeodactylum tricornutum Bohlin and Thalassiosira pseudonana.Intellectual Merit: The establishment of a QS-like communication system will bring in a new perspective to our views on phytoplankton ecology beyond our current paradigm of bottom-up and top-down controls or competitive interactions. Results from this study will also influence our views on the factors controlling phytoplankton population diversity, as we will now have to consider the role of inter-species communication. Funding through an EAGER proposal will provide support for exploratory, high-risk research to obtain a minimum set of data as proof of concept of QS in phytoplankton.Broader Impacts: The PIs will establish a collaboration with a local high school. They seek to remedy the mismatch in the way biology is taught and practiced by teaching high-school students to examine biological phenomena from a systems perspective. This will better prepare them for potential science careers in the information era while fostering their curiosity about their local marine ecosystem.

最近的发现表明，细胞间通讯从物种内延伸到王国间水平，并在形态、代谢状态和种群结构的变化等种群范围的生物事件中发挥着关键作用。群体感知（QS）是一种通信过程，允许单个细胞作为分散网络协作运行。对原核生物和最近的真菌的研究表明，QS 调节关键生物过程的时间，例如菌落形成、孢子形成、形态变化、致病性和有性生殖。在海洋环境中，QS 已在细菌中得到证实，但浮游植物种群尚未考虑到这种水平的相互合作。鉴于有关细胞间通讯关键作用的文献不断涌现，我们应该重新考虑如何看待海洋浮游植物。迄今为止，海洋浮游植物细胞间相互作用的研究主要集中在与其他物种竞争的化学信号（例如化感作用）、捕食威慑和环境压力预警系统上。有多种间接证据支持浮游植物中的 QS，例如细胞分裂的时间、密度依赖性化感作用和程序性细胞死亡。然而，据我们所知，还没有直接的实验来确定浮游植物是否可以在合作联盟中发挥作用。它们是否具有群体感应类型的通信来调节物种内过程以及调节物种间相互作用？循环浮游植物群落的建立是否是因为这些物种能够与每个发挥特定作用以维持种群的成员进行交流？这些问题很难解决，但对我们理解浮游植物生态学具有深远的影响。该项目将通过检查特定生物事件的自诱导过程（QS 的基本租户）来测试浮游植物是否具有 QS 系统。 PI 将通过使用浮游植物生态和生理测量以及最先进的生物信息和基因组工具检查两个特定区域来测试这一点：I。基于与其他生物体 QS 相关基因的同源性，在现有基因组和基因表达数据库中对候选浮游植物 QS 相关基因进行广泛搜索。 PI 将进行详细分析，以明确地将这些 QS 调节途径的同源物以及 QS 化合物和转录/翻译调节因子的少数已知生物合成途径映射到浮游植物基因组上。结果将作为浮游植物细胞间通讯比较基因组学研究的一部分，并且任何候选基因在 QS 中的可能作用将通过下面详述的实验进行测试 (2)。使用实验方法建立硅藻物种细胞过程的自诱导。 PI 将重点关注使用两种模型硅藻物种（三角褐指藻 Boh​​lin 和假微型海链藻）进行无菌培养的自诱导生长、细胞形态、化感作用和生物膜形成。 智力优点：建立类似 QS 的通信系统将为我们对浮游植物生态学的看法带来超越当前范式的新视角 自下而上和自上而下的控制或竞争性互动。这项研究的结果也将影响我们对控制浮游植物种群多样性的因素的看法，因为我们现在必须考虑物种间交流的作用。通过 EAGER 提案提供的资金将为探索性高风险研究提供支持，以获得最低限度的数据集，作为浮游植物 QS 概念的证明。 更广泛的影响：PI 将与当地高中建立合作关系。 他们试图通过教导高中生从系统角度审视生物现象来弥补生物学教学和实践方式的不匹配。这将使他们更好地为信息时代潜在的科学职业做好准备，同时培养他们对当地海洋生态系统的好奇心。