Collaborative Research: VIDA Seagrass: Viral Infection Dynamics Among Seagrass

海草是海洋开花植物（或被子植物），它们创造了广阔的水下草甸，构成了沿海海洋高产和有价值的生态系统的基础。与被子植物主导植物多样性的陆地系统不同，海草是海洋环境中唯一的开花植物。基于病毒感染对陆生植物的深刻影响，病毒有望影响海草生态。然而，目前尚无研究海草病毒感染动态及病毒对海草健康影响的文献。本项目通过对海草-病毒相互作用的野外和实验室研究提供了关于海草-病毒相互作用的基础知识（即海草，顶极物种和关键生态系统工程师）和海草病毒X (TVX)，这是目前唯一从实验研究中报道的海草病毒)。由于缺乏海草病毒研究系统，科学界一直无法了解是哪些因素导致了海洋被子植物的病毒感染。通过建立第一个海草病毒研究系统，这是一种几乎一无所知的新型病毒宿主病理系统，该项目有助于更全面地了解海草生态，并作为研究通过测序工作发现的越来越多的海草病毒的模型。本项目培养博士后1名，研究生2名，本科生6名。通过开放获取渠道传播结果和数据，为更广泛的社区提供信息，并为科学家自己的研究提供数据，以推动海草病毒学领域的发展。该项目还鼓励教育工作者和学生参与旨在提高STEM领域中代表性不足群体参与度的项目。来自杰克逊维尔教师实习计划的教师们正在参与到深入研究海草生物学的课程开发中。来自女童社团、女童军和南佛罗里达大学海洋学女童营的学生们以公民科学家的身份参与其中，拍摄坦帕湾的海草生态系统，并将他们的观察结果提交给海草观测者网站。该项目还提高了对海草生态系统的认识，并通过一年一度的圣彼得堡科学节的实践活动挑战公众对所有病毒都是致病的看法。海草与病毒的相互作用正在通过两层方法进行调查，包括在佛罗里达州坦帕湾进行实地研究和微观实验。实地调查的重点是阐明龟草-TVX相互作用的性质（积极、中性或消极），以及在TVX持续存在至少5年的自然种群中龟草基因型多样性与病毒分布之间的关系。在两年内每月监测一次TVX负荷，以评估病毒负荷与龟草基因型和性能（生长、健康、繁殖努力）以及非生物参数的关系。所调查的龟草甸包含tvx阳性和阴性标本，从而提供了一个具有同质环境特征的完美自然实验室，可以探索病毒感染的驱动因素。鉴于环境变化可能改变宿主-微生物的相互作用，互补的微观实验正在评估海龟对TVX感染的生理（生存、光化学能力、细胞反应）和分子（转录组学）水平在正常条件下的受控环境和盐度变化的背景下的反应，盐度变化是一个重要的海草胁迫源。微观实验也提供了海草基因表达和细胞代谢物在病毒感染反应中的测量的第一个概况。预期结果对了解海草在全球气候变化和人为压力下的生产和恢复能力具有直接意义。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。

Seagrasses are marine flowering plants (or angiosperms) that create expansive underwater meadows that form the basis of highly productive and valuable ecosystems in coastal oceans. Unlike terrestrial systems where angiosperms dominate plant diversity, seagrasses are the only flowering plants in marine environments. Based on the profound impacts of viral infections on terrestrial plants, viruses are expected to influence seagrass ecology. However, no prior work has investigated viral infection dynamics in seagrasses or the impact of viruses on seagrass health. This project provides fundamental knowledge about seagrass-virus interactions through field and laboratory studies of Thalassia testudinum (i.e., turtlegrass, a climax species and key ecosystem engineer), and turtlegrass virus X (TVX), the only seagrass virus currently reported from experimental research. The lack of a seagrass-virus study system has kept the scientific community from learning which factors drive viral infection in marine angiosperms. By establishing the first seagrass-virus study system, a novel virus-host pathosystem for which virtually nothing is known, this project contributes to a more comprehensive understanding of seagrass ecology and serves as a model for investigating the growing number of seagrass viruses discovered through sequencing efforts. This multifaceted project trains one postdoctoral researcher, two graduate students, and six undergraduate students. Dissemination of results and data through open access channels informs the broader community and provides scientists with data for their own research to propel the field of seagrass virology. This project also engages educators and students participating in programs that strive to increase participation from underrepresented groups in STEM fields. Teachers from the Jacksonville Teacher Residency Program are getting involved through development of lessons that dive into seagrass biology. Students from Girls Incorporated, Girl Scouts, and the University of South Florida’s Oceanography Camp for Girls are participating as citizen scientists by photographing Tampa Bay’s seagrass ecosystems and contributing their observations to the Seagrass Spotter website. This project also increases awareness of seagrass ecosystems and challenges the public perception that all viruses are pathogenic through hands-on activities at the annual St. Petersburg Science Festival.Seagrass-virus interactions are being investigated through a two-tiered approach involving field studies in Tampa Bay, Florida and microcosm experiments. Field surveys focus on elucidating the nature of turtlegrass-TVX interactions (positive, neutral or negative) and the relationship between turtlegrass genotypic diversity and virus distribution in a natural population where TVX has persisted for at least five years. TVX load is monitored bimonthly over two years to assess how viral load relates to turtlegrass genotype and performance (growth, health, reproductive effort), and abiotic parameters. The investigated turtlegrass meadow contains TVX-positive and negative specimens, thus providing a perfect natural laboratory with homogenous environmental characteristics that allow exploration of the drivers of viral infection. Given that environmental changes may alter host-microbe interactions, complementary microcosm experiments are evaluating turtlegrass responses to TVX infection at the physiological (survival, photochemical capacity, cellular responses) and molecular (transcriptomic) levels in a controlled environment under normal conditions and in the context of salinity changes, an important seagrass stressor. Microcosm experiments also provide the first profiles of seagrass gene expression and measurement of cellular metabolites in response to viral infection. Expected results have direct implications for understanding seagrass production and resilience in the face of global climate change and anthropogenic stress.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.