Collaborative Research: VIDA Seagrass: Viral Infection Dynamics Among Seagrass

海草是海洋开花植物(或被子植物)，它们形成广阔的水下草地，构成沿海海洋高生产力和高价值生态系统的基础。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开花的植物。基于病毒感染对陆地植物的深刻影响，病毒有望影响海草生态。然而，以前没有研究过海草中的病毒感染动态或病毒对海草健康的影响。该项目通过对地中海藻(即顶极物种和关键生态系统工程师龟草)和龟草病毒X(TVX)的野外和实验室研究，提供了关于海草与病毒相互作用的基本知识。由于缺乏海草病毒研究系统，科学界无法了解哪些因素导致海洋被子植物感染病毒。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，并成为调查通过测序工作发现的越来越多的海草病毒的模型。这个多方面的项目培养了一名博士后研究员、两名研究生和六名本科生。通过开放获取渠道传播结果和数据向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。该项目还让教育工作者和学生参与旨在增加STEM领域中代表性不足群体的参与的项目。杰克逊维尔教师实习计划的教师们正在通过开发深入研究海草生物学的课程来参与其中。来自女孩公司、女孩童子军和南佛罗里达大学女孩海洋营的学生以公民科学家的身份参与拍摄坦帕湾的海草生态系统，并将他们的观察结果贡献给海草探测器网站。该项目还提高了人们对海草生态系统的认识，并通过在一年一度的圣彼得堡科学节上的亲身实践活动挑战了公众对所有病毒都是致病的看法。正在通过两个层次的方法研究海草与病毒的相互作用，包括在佛罗里达州坦帕湾的实地研究和微观世界实验。实地调查的重点是阐明龟花与TVX相互作用的性质(正、中性或负)，以及TVX持续至少五年的自然种群中龟花基因多样性与病毒分布之间的关系。在两年多的时间里，每两个月监测一次TVX病毒载量，以评估病毒载量与龟板草的基因型和性能(生长、健康、繁殖努力)和非生物参数之间的关系。被调查的龟尾草草甸含有TVX阳性和阴性标本，因此提供了一个完美的天然实验室，具有同质的环境特征，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，互补性微观世界实验正在正常条件下和在盐度变化的背景下，从生理(生存、光化学能力、细胞反应)和分子(转录)水平评估海草对TVX感染的反应，盐度变化是海草的一个重要压力来源。微观世界实验还提供了海草基因表达的第一个概况，并测量了细胞代谢物对病毒感染的反应。预期结果对理解海草产量和应对全球气候变化和人为压力具有直接影响。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.