NSF Postdoctoral Fellowship in Biology FY 2020: Carbon and nitrogen source switching in a microbe-bivalve-plant symbiosis

这一行动为NSF 2020财年生物学博士后研究奖学金提供了资金，综合研究调查了基因组、环境和表型之间相互作用的生命规则。该奖学金支持研究员的研究和培训，这些研究员将以创新的方式为生活规则领域做出贡献。这位研究员的项目将解决人类从化肥、污水或其他来源向沿海水域输入营养物质可能会如何影响一种名为绿藻的蛤类。灵蚌生活在沙子或泥土中，在它们的鳃里寄生着共生细菌。这是一种互惠互利的关系，因为细菌使用硫来制造其他所需的分子。灵芝通常生活在海草的根部，并促进生长和存活，因为它们从沉积物中去除的硫化物是有毒的。健康的海草床起着重要的作用，可以减少侵蚀，为许多具有商业和娱乐价值的重要鱼类和贝类提供栖息地。该项目将分析灵蚌和共生细菌如何应对沿海环境的变化，以及这种变化可能如何扩大规模，以影响海草生态系统。了解这些关系对于保护和修复工作将是重要的。为了将研究扩大到代表性不足的群体和更广泛的社区，该研究员将就该项目开发一个公共展览，为公共科学传播计划做出贡献，并参加海岸恢复从业者会议。该奖学金项目将利用细菌-绿藻-海草共生来解决三个具体问题：(A)海草床的营养状况是否会改变绿藻及其硫氧化、固氮共生体的碳和氮来源？(B)海草床的营养状况是否改变了共生体在荧光鳃微生物群中的比例？以及(C)这些对荧光素新陈代谢和微生物群落的改变是否会影响海草的生长和状况？该项目将包括一项关于沿海海草床人为营养丰富梯度的实地调查，并辅之以一项中层生态系统的营养丰富实验。将使用碳和氮稳定同位素分析、基因表达分析、基因测序、沉积物孔隙水化学以及海草生长和条件的标准指标来评估低营养和高营养条件对海藻营养的影响；海藻微生物群落中共生体和其他伴生细菌的多样性；以及海草对沉积物生物地球化学和海草健康的影响。该研究员将接受分子生物学技术和生物信息学分析方面的培训，并在项目管理、指导和教学方面提供建议。该研究员还将参与公共推广和修复计划，这些计划将加强研究成果与更广泛社区的交流。该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准进行评估，被认为值得支持。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. The fellow’s project will address how human input of nutrients from fertilizer, sewage, or other sources into coastal waters may affect a group of clams called lucinids. Lucinid clams live buried in sand or mud and host symbiotic bacteria inside their gills. This is a mutually beneficial relationship because the bacteria use sulfur to make other needed molecules. Lucinid clams often live among the roots of seagrasses and enhance growth and survival because the sulfur compounds they remove from sediment are toxic. Healthy seagrass beds serve important functions by reducing erosion and providing a habitat for many commercially and recreationally important fish and shellfish. This project will analyze how lucinid clams and the symbiotic bacteria respond to changes in the coastal environment and how this may scale up to impact seagrass ecosystems. Understanding the relationships will be important for conservation and restoration efforts. To enhance the reach of the research to underrepresented groups and the wider community, the fellow will develop a public exhibit on the project, contribute to public science communication programs, and participate in coastal restoration practitioner meetings. The fellowship project will use the bacteria-lucinid-seagrass symbiosis to address three specific questions: (a) Does the nutrient status of seagrass beds alter carbon and nitrogen sourcing by lucinids and their sulfur-oxidizing, nitrogen-fixing symbionts? (b) Does the nutrient status of seagrass beds change the proportional representation of symbionts in the lucinid gill microbiome? and (c) Do these alterations to lucinid metabolism and microbiome scale up to affect seagrass growth and condition? The project will comprise a field survey across a gradient of anthropogenic nutrient enrichment in coastal seagrass beds, complemented by a nutrient enrichment experiment in mesocosms. Carbon and nitrogen stable isotope analysis, gene expression assays, gene sequencing, sediment porewater chemistry, and standard metrics of seagrass growth and condition will be used to assess the effect of low- and high-nutrient conditions on the relative contributions of chemoautotrophy and nitrogen fixation to lucinid nutrition; the diversity of symbionts and other gill-associated bacteria in lucinid microbiomes; and consequent effects of lucinids on sediment biogeochemistry and seagrass health. The fellow will receive training in molecular biology techniques and bioinformatic analyses as well as advising in project management, mentoring, and teaching. The fellow will also participate in public outreach and restoration programs that will enhance the communication of research results to the broader community.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.