Collaborative Research: VIDA Seagrass: Viral Infection Dynamics Among Seagrass

海草是海洋开花植物（或被子植物），创造了广阔的水下草甸，形成了沿海海洋高产和宝贵生态系统的基础。与陆地系统中被子植物占主导地位的植物多样性不同，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，没有先前的工作调查海草中的病毒感染动态或病毒对海草健康的影响。该项目通过对海樽海苔（Thalassia testudinum）的实地和实验室研究提供了关于海草-病毒相互作用的基本知识（即，龟草，一种顶极物种和关键生态系统工程师），以及龟草病毒X（TVX），这是目前实验研究中报道的唯一海草病毒。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中的病毒感染。通过建立第一个海草病毒研究系统，一种新的病毒宿主病理系统，几乎一无所知，该项目有助于更全面地了解海草生态，并作为一个模型，调查越来越多的海草病毒发现通过测序工作。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，为更广泛的社区提供信息，并为科学家提供数据，以推动海草病毒学领域的研究。 该项目还吸引教育工作者和学生参与旨在提高STEM领域代表性不足群体参与度的计划。来自杰克逊维尔教师居住计划的教师正在参与开发深入海草生物学的课程。来自女童军、女童子军和南佛罗里达大学的女童海洋学夏令营的学生作为公民科学家参加，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观测网站。该项目还提高了对海草生态系统的认识，并通过在每年一度的彼得堡科学节上开展的实际活动，挑战了公众认为所有病毒都是致病性的看法，目前正在通过两级办法调查海草与病毒的相互作用，包括在佛罗里达的坦帕湾进行实地研究和进行微观实验。实地调查的重点是阐明的性质，turtlegrass-TVX相互作用（积极的，中性或消极的）和turtlegrass-TVX已经持续了至少五年的自然种群中的turtlegrass-TVX基因型多样性和病毒分布之间的关系。TVX载量监测两个月超过两年，以评估病毒载量如何与龟鳖草基因型和性能（生长，健康，生殖努力），和非生物参数。被调查的斑鸠草草甸包含TVX阳性和阴性标本，从而提供了一个完美的天然实验室，具有均匀的环境特征，可以探索病毒感染的驱动因素。考虑到环境变化可能会改变宿主-微生物的相互作用，补充的微观实验正在评估在正常条件下和在盐度变化（一个重要的海草应激源）的背景下，在受控环境中，在生理（生存，光化学能力，细胞反应）和分子（转录组学）水平上对TVX感染的响应。微宇宙实验还提供了海草基因表达的第一个概况和测量细胞代谢产物对病毒感染的反应。预期结果对理解海草生产和面对全球气候变化和人为压力的恢复力有直接影响。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.