Collaborative Research: Constitutive and Inducible Predation Defenses in Cyanobacteria

陆生植物有多种复杂的防御捕食者和病原体的机制，但水生生态系统中光合微生物的防御机制却鲜为人知。聚藻球菌是水生/海洋蓝藻，对全球初级生产力做出了重大贡献。本项目将采用两种主要方法来研究聚球菌对原生捕食者的防御。实验将检验细胞表面蛋白提供组成性（连续表达）防御的机制，并分析这种防御在聚球菌菌株和不同捕食者类型之间的普遍性。其次，共培养技术，即在捕食者存在的情况下培养聚球菌，将用于表征可能在捕食反应中产生的基于蛋白质的诱导防御。聚集体的形成作为一种可能的诱导防御由聚珠球菌也将在现场和实验室设置检查。聚集体的形成对于浮游生物群落的生物地球化学和生态功能是重要的，因为聚集体可以是独特的生物地球化学过程的场所。这项研究在许多层面上是交叉的：它在受控的实验室和自然环境中检查了本构性和诱导性防御；它利用一套可用的聚球菌基因组来进行微生物防御过程的机制研究；它代表了生态学和基因组学研究微生物相互作用的综合方法，微生物相互作用是生物地球化学循环和水生生态系统生物多样性维持的基础。该项目的更广泛影响包括对研究生和本科生的支持，包括香农角海洋中心海洋科学本科多元文化计划（MIMSUP）的少数民族参与者。其他影响还包括为中小学生开发教学模块，维护和分发文化收藏品。

Terrestrial plants have diverse and sophisticated mechanisms for defending against predation and pathogens, but the defenses of photosynthetic microbes in aquatic ecosystems are much less well understood. Synechococcus are aquatic/marine cyanobacteria that substantially contribute to global primary productivity. This project will employ two main approaches to study Synechococcus defenses against protist predators. Experiments will examine the mechanism(s) by which cell surface proteins provide a constitutive (continuously expressed) defense and assay the generality of this defense among Synechococcus strains and against diverse predator types. Secondly, co-culture techniques, in which Synechococcus are grown in the presence of predators, will be used to characterize protein-based induced defenses that may arise in response to predation. The formation of aggregates as a possible induced defense by Synechococcus will also be examined in field and laboratory settings. Aggregate formation is important for the biogeochemistry and ecological functioning of planktonic communities since aggregates can be the site of unique biogeochemical processes. The research is cross-cutting on a number of levels: it examines constitutive and induced defenses in both controlled laboratory and natural settings; it leverages the suite of available Synechococcus genomes to enable a mechanistic investigation of microbial defense processes; and it represents a synthesis of ecological and genomic approaches to the study of microbial interactions that are fundamental to biogeochemical cycling and the maintenance of biodiversity in aquatic ecosystems. Broader impacts of this project include support of graduate and undergraduate students, including ethnic minority participants in Shannon Point Marine Center's Multicultural Initiatives in Marine Science Undergraduate Program (MIMSUP). Other impacts include development of instructional modules for elementary and high school students, and maintenance and distribution of culture collections.