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

该行动资助了NSF 2020财年生物学博士后研究奖学金，研究基因组，环境和表型之间相互作用的生命规则的综合研究。该奖学金支持将以创新方式对生活规则领域作出贡献的研究员的研究和培训。这名研究员的项目将研究人类从肥料、污水或其他来源向沿海水域输入的营养物质如何影响一种名为lucinids的蛤蜊。Lucinid蛤蜊生活在沙子或泥土中，它们的鳃里有共生细菌。这是一种互惠互利的关系，因为细菌利用硫来制造其他所需的分子。Lucinid蛤蜊通常生活在海草的根部，因为它们从沉积物中去除的硫化合物是有毒的，所以它们能促进生长和存活。健康的海草床通过减少侵蚀和为许多商业和娱乐重要的鱼类和贝类提供栖息地发挥重要作用。该项目将分析lucinid蛤和共生细菌如何对沿海环境的变化做出反应，以及这种变化如何影响海草生态系统。了解它们之间的关系对保护和恢复工作非常重要。为了提高研究对代表性不足的群体和更广泛的社区的影响，研究员将为该项目举办公开展览，为公共科学交流项目做出贡献，并参加海岸恢复从业者会议。研究金项目将利用细菌-萤光素-海草共生关系来解决三个具体问题：(a)海草床的营养状况是否改变萤光素及其硫氧化、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lucinid gill微生物组中共生体的比例代表？(c)这些对荧光素代谢和微生物组的改变是否会影响海草的生长和状况？该项目将包括对沿海海草床的人为营养物富集梯度进行实地调查，并辅之以中生态系统的营养物富集实验。碳氮稳定同位素分析、基因表达测定、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将用于评估低营养和高营养条件对化学自养和固氮对lucinid营养的相对贡献的影响；lucinid菌群中共生体和其他鳃相关细菌的多样性以及随之而来的lucinids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宣传和修复项目，以加强与更广泛社区的研究成果交流。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.