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: 1831552
• 负责人: John Meeks
• 金额: $ 53.8万
• 依托单位: University of California-Davis
• 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=1831552&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.

只有少数几种植物可以与固氮细菌形成有益的伙伴关系。这些包括几种苔藓植物，蕨类植物，苏铁和一小部分开花植物。由于它们对农作物的重要性，大量研究集中在豆类与为它们固定氮的细菌之间的关系 - 根瘤菌。关于植物和蓝细菌之间更广泛的伙伴关系，知之甚少。由于蓝细菌通常比根瘤菌更少依赖植物宿主，因此它们可能是工程有助于对农作物植物固定有助于氮的好伙伴。但是，我们目前对植物 - 苯基细菌伙伴关系的理解很差。有用的蓝细菌的物种和遗传多样性几乎没有探索。同样，与这些伙伴关系有关的植物基因仍然未知。霍恩沃尔特（Hornworts）是三个苔藓植物谱系之一，是研究植物 - 细菌关系的出色系统。这项研究将研究Hornwort-Cyanobacterium伙伴关系的系统发育，功能和遗传方面。通过这样做，这项研究将探讨一系列问题，这些问题将为这些独特的植物如何与细菌伴侣相互作用以固定氮。一名博士后研究员，三名毕业生，十个本科生和五名高中生将接受培训。与纽约州科学教师协会合作，将制作一个教育视频。该视频将展示各种形式的植物 - 细菌关系。这项研究的目标是首先揭示霍恩沃尔特和氰基群的系统发育多样性。然后阐明共生氮固定的功能多样性。最后，这项研究将揭示霍恩沃特与其氰基之间关联的遗传成分。研究人员将使用系统基因组方法重建霍恩沃特生活树。然后，对于每个Hornwort样本，将表征氰基群体的遗传多样性。比较Hornwort和Cyanobiont多样性将揭示宿主 - 共生特异性。该研究还将研究共同进化的模式以及氰基共生在霍恩沃特进化中的作用。接下来，将使用人口和缩影研究来测试Hornwort微生物组多样性，环境变量和氮固定速率之间的相互作用。最后，将隔离多种纯霍恩沃特和氰基培养物。一旦孤立，它们的共生物将在实验室的受控环境条件下重组。将生成时间课程RNA-seq数据，以识别推定的基因，这些基因是共生建立的核心，并与共生行为的变化有关。这项研究的结果将能够在所有三种主要形式的植物 - 微生物互动中进行比较，以充分表征共生的进化和遗传基础。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力和更广泛影响的评估来通过评估来获得支持的。