Collaborative Research: Identifying the basis of fitness against protozoan grazing in cyanobacteria: From quantitative genomics to molecular mechanisms

合作研究：确定蓝藻细菌适应原生动物放牧的基础：从定量基因组学到分子机制

• 批准号: 1754946
• 负责人: James Golden
• 金额: $ 42.69万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1754946&HistoricalAwards=false
• 关键词: Collaborative; Research; Identifying; basis; fitness

Cyanobacteria are important photosynthetic microorganisms in aquatic environments, where they occupy a central position at the base of the food web. In addition, certain species produce toxins and are capable of forming harmful algal blooms. Occurrences of these blooms are expected to increase in the future due to eutrophication and increasing temperatures. One of the factors controlling cyanobacterial populations is predation, but very little is known about the biochemical and genetic mechanisms governing the interactions between cyanobacteria and their predators. The researchers will identify cyanobacterial genes that affect their susceptibility to predators in order to understand predation mechanisms. This knowledge will be useful in guiding the management of recreational and drinking freshwater resources, and that of large scale outdoor culturing of cyanobacteria for biotechnological applications, which is often hampered by predators. Because toxic algal blooms are of general public interest, the researchers will incorporate aspects of this project into their teaching and outreach presentations to engage students and the public in the process of science and its application to environmental problems. They will also develop a module of classes for underrepresented high school students that will introduce them to the presence, abundance, and role of bacteria in aquatic environments. This project concerns physiological mechanisms underlying the resistance of cyanobacteria to predation by protists. Specifically, the main objective of this project is to identify genes and processes governing the fitness of the unicellular cyanobacterium Synechococcus elongatus under selective pressure by amoebal and ciliate predators. The investigators have developed laboratory model systems to study grazing interactions and will study these interactions with state-of-the-art random barcode transposon mutagenesis (RB-TnSeq) and omics approaches, as well as genetic, biochemical, and physiological methods. Their preliminary work on amoebal grazing has pointed to the importance of several components of the cell surface in increasing fitness under grazing conditions. The investigators will build upon these preliminary findings and identify the mechanism of grazing resistance to amoebal predators in S. elongatus O-antigen mutants and other mutants disrupted in genes identified by RB-TnSeq. They will perform similar analyses to identify genes and processes affecting cyanobacterial fitness in the presence of a swimming ciliate grazer. These comparative studies will provide major insight into cyanobacterial strategies for evasion of predators. The investigators will also incorporate the research into modules for high school students and involve undergraduates, graduates and postdoctoral scholars in the research.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.

蓝藻是水生环境中重要的光合微生物，在食物网的底层占据中心地位。此外，某些物种产生毒素，能够形成有害的藻华。由于富营养化和温度上升，预计今后这些水华的发生率将增加。控制蓝藻种群的因素之一是捕食，但很少有人知道蓝藻和它们的捕食者之间的相互作用的生化和遗传机制。研究人员将确定影响其对捕食者易感性的蓝藻基因，以了解捕食机制。这方面的知识将是有用的，指导管理的娱乐和饮用淡水资源，以及大规模的户外培养蓝藻的生物技术应用，这往往是由捕食者阻碍。由于有毒藻华是公众普遍关心的问题，研究人员将把这个项目的各个方面纳入他们的教学和宣传演讲，让学生和公众参与科学及其在环境问题中的应用。他们还将为代表性不足的高中生开发一个课程模块，向他们介绍细菌在水生环境中的存在、丰度和作用。本计画探讨蓝细菌抵抗原生生物捕食的生理机制。具体来说，这个项目的主要目标是确定基因和过程管理的单细胞蓝藻Synechococcus elongatus的选择压力下，由变形虫和纤毛虫捕食者的健身。研究人员开发了实验室模型系统来研究放牧相互作用，并将研究这些相互作用与最先进的随机条形码转座子诱变（RB-TnSeq）和组学方法，以及遗传，生化和生理方法。他们对阿米巴放牧的初步研究指出，在放牧条件下，细胞表面的几种成分在增加适应性方面具有重要意义。研究人员将在这些初步发现的基础上，确定S。细长体0-抗原突变体和其他突变体在通过RB-TnSeq鉴定的基因中被破坏。他们将进行类似的分析，以确定在游泳纤毛虫食草动物存在下影响蓝藻适应性的基因和过程。这些比较研究将为蓝藻逃避捕食者的策略提供重要的见解。研究人员还将把这项研究纳入高中学生的模块，并让本科生、研究生和博士后学者参与研究。该奖项反映了NSF的法定使命，并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，被认为值得支持。

项目成果

The circadian clock and darkness control natural competence in cyanobacteria

• DOI: 10.1038/s41467-020-15384-9
• 发表时间: 2020-04-03
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Taton, Arnaud;Erikson, Christian;Golden, Susan S.
• 通讯作者: Golden, Susan S.