Collaborative Research: Dimensions: Integrating phylogenetics, ecophysiology and transcriptomics to understand the diversity of hornwort-cyanobacterium symbiosis

合作研究：维度：整合系统发育学、生态生理学和转录组学，了解金鱼藻-蓝藻共生的多样性

• 批准号: 1831416
• 负责人: Jed Sparks
• 金额: $ 11.14万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1831416&HistoricalAwards=false
• 关键词: Collaborative; Research; Dimensions; Integrating; phylogenetics

Only a few remarkable plants can form beneficial partnerships with nitrogen-fixing bacteria. These include a few species of bryophytes, ferns, cycads, and a small group of flowering plants. Because of their importance to crops, a lot of research has focused on the relationship between legumes and the bacteria that fix nitrogen for them - rhizobia. Much less is known about an even more widespread partnership between plants and cyanobacteria. Because cyanobacteria are generally less dependent on the plant host than rhizobia, they could be an excellent partner for engineering helpful nitrogen fixation into crop plants. However, our current understanding of plant-cyanobacterium partnerships is poor. The species and genetic diversity of helpful cyanobacteria is virtually unexplored. Similarly, the plant genes involved in these partnerships remain unknown. Hornworts, one of the three bryophyte lineages, are an outstanding system to study plant-cyanobacterial relationships. This study will investigate phylogenetic, functional, and genetic aspects of the hornwort-cyanobacterium partnership. In doing so, the research will explore an array of questions that will provide new insights into how these unique plants interact with their bacterial partners to fix nitrogen. One postdoctoral fellow, three graduate, ten undergraduate, and five high school students will be trained. In partnership with the Science Teachers Association of New York State, an educational video will be made. This video will showcase the various forms of plant-cyanobacterium relationships. The goals of this research are first to uncover the phylogenetic diversity of hornworts and cyanobionts. Then to elucidate the functional diversity of symbiotic nitrogen-fixation. Finally, the research will reveal the genetic components of the association between hornworts and their cyanobionts. The researchers will reconstruct the hornwort tree-of-life using a phylogenomic approach. Then, for each hornwort sample, the genetic diversity of the cyanobiont community will be characterized. Comparing the hornwort and cyanobiont diversity will shed light on host-symbiont specificity. The research will also study patterns of co-evolution, and the roles of cyanobacterial symbiosis in hornwort evolution. Next, population and microcosm studies will be used to test the interaction among hornwort microbiome diversity, environmental variables, and nitrogen-fixation rates. Finally, multiple pure hornwort and cyanobiont cultures will be isolated. Once isolated, their symbioses will be reconstituted under controlled environmental conditions in the laboratory. Time-course RNA-seq data will be generated to identify putative genes that are core for symbiosis establishment and linked to variation in symbiotic behaviors. The results of this research will enable comparisons across all three major forms of plant-microbe mutualistic interaction to fully characterize the evolutionary and genetic underpinnings of symbioses.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.

只有少数非凡的植物可以与固氮细菌形成有益的伙伴关系。其中包括一些苔藓植物、蕨类植物、苏铁植物和一小群开花植物。由于它们对农作物的重要性，许多研究都集中在豆类与为其固氮的细菌（根瘤菌）之间的关系。关于植物和蓝藻之间更广泛的伙伴关系，人们知之甚少。由于蓝细菌通常比根瘤菌对植物宿主的依赖性较小，因此它们可能是对农作物进行有益固氮改造的绝佳伙伴。然而，我们目前对植物-蓝藻伙伴关系的了解还很有限。有用的蓝藻细菌的种类和遗传多样性实际上尚未被探索。同样，参与这些伙伴关系的植物基因仍然未知。金鱼藻是三个苔藓植物谱系之一，是研究植物与蓝藻关系的杰出系统。这项研究将调查金鱼藻-蓝藻伙伴关系的系统发育、功能和遗传方面。在此过程中，该研究将探索一系列问题，这些问题将为这些独特的植物如何与其细菌伙伴相互作用以固氮提供新的见解。将培养一名博士后、三名研究生、十名本科生和五名高中生。将与纽约州科学教师协会合作制作教育视频。该视频将展示植物与蓝藻关系的各种形式。这项研究的目标首先是揭示金鱼藻和蓝生物的系统发育多样性。进而阐明共生固氮的功能多样性。最后，该研究将揭示金鱼藻与其蓝藻生物之间关联的遗传成分。研究人员将利用系统发育学方法重建金鱼草生命树。然后，对于每个金鱼藻样本，将描述蓝藻生物群落的遗传多样性。比较金鱼藻和蓝藻生物的多样性将有助于揭示宿主-共生体的特异性。该研究还将研究共同进化的模式以及蓝藻共生在金鱼藻进化中的作用。接下来，种群和微观世界研究将用于测试金鱼藻微生物组多样性、环境变量和固氮率之间的相互作用。最后，将分离出多种纯金鱼草和蓝藻培养物。一旦分离，它们的共生关系将在实验室受控的环境条件下重建。将生成时程 RNA-seq 数据，以识别作为共生建立核心并与共生行为变化相关的推定基因。这项研究的结果将能够对植物-微生物互利相互作用的所有三种主要形式进行比较，以充分表征共生体的进化和遗传基础。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进行评估，被认为值得支持以及更广泛的影响审查标准。