RUI: Collaborative Research: Trait differentiation and local adaptation to depth within meadows of the foundation seagrass Zostera marina

RUI：合作研究：大叶草码头基础草甸内的性状分化和局部适应深度

• 批准号: 1851043
• 负责人: Randall Hughes
• 金额: $ 33.67万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851043&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Trait; differentiation

Understanding how species cope with spatial variation in their environment (e.g. gradients in light and temperature) is necessary for informed management as well as for predicting how they may respond to change. This project will examine how key traits vary with depth in common eelgrass (Zostera marina), one of the most important foundation species in temperate nearshore ecosystems worldwide. The investigators will use a combination of experiments in the field and lab, paired with fine-scale molecular analyses, to determine the genetic and environmental components of seagrass trait variation. This work will provide important information on the microevolutionary mechanisms that allow a foundation species to persist in a variable environment, and thus to drive the ecological function of whole nearshore communities. The Northeastern University graduate and Keene State College (KSC) undergraduate students supported by this project will receive training in state-of-the-art molecular techniques, as well as mentorship and experience in scientific communication and outreach. A significant portion of KSC students are from groups under-represented in science. Key findings of the research will be incorporated into undergraduate courses and outreach programs for high school students from under-represented groups, and presented at local and national meetings of scientists and stakeholders. Local adaptation, the superior performance of "home" versus "foreign" genotypes in a local environment, is a powerful demonstration of how natural selection can overcome gene flow and drift to shape phenotypes to match their environment. The classic test for local adaptation is a reciprocal transplant. However, such experiments often fail to capture critical aspects of the immigration process that may mediate realized gene flow in natural systems. For example, reciprocal transplant experiments typically test local and non-local phenotypes at the same (often adult) life history stage, and at the same abundance or density, which does not mirror how dispersal actually occurs for most species. In real populations, migrants (non-local) often arrive at low numbers compared to residents (local), and relative frequency itself can impact fitness. In particular, rare phenotypes may experience reduced competition for resources, or relative release from specialized pathogens. Such negative frequency dependent selection can reduce fitness differences between migrants and residents due to local adaptation, and magnify effective gene flow, thus maintaining greater within-population genetic diversity. The investigators will combine spatially paired sampling and fine-scale molecular analyses to link seed/seedling trait variation across the depth gradient at six meadows to key factors that may drive these patterns: local environmental conditions, population demography, and gene flow across depths. The team will then experimentally test the outcome of cross-gradient dispersal in an ecologically relevant context, by reciprocally out-planting seeds from different depths and manipulating relative frequency in relation to both adults and other seedling lineages. The possible interaction between local adaptation and frequency-dependence is particularly relevant for Zostera marina, which represents one of the best documented examples of the ecological effects of genetic diversity and identity. Further, a better understanding of seagrass trait differentiation is not simply a matter of academic interest, but critical to successful seagrass restoration and conservation.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.

了解物种如何科普环境中的空间变化（例如光照和温度梯度）对于明智的管理以及预测它们如何应对变化是必要的。该项目将研究全球温带近岸生态系统中最重要的基础物种之一--大叶藻（Zostera marina）的关键性状如何随深度而变化。研究人员将结合实地和实验室的实验，结合精细的分子分析，来确定海草性状变异的遗传和环境成分。这项工作将提供重要的信息的微进化机制，使一个基础物种坚持在一个可变的环境，从而推动整个近岸社区的生态功能。该项目支持的东北大学毕业生和基恩州立学院（KSC）本科生将接受最先进的分子技术培训，以及科学交流和推广方面的指导和经验。KSC学生的很大一部分来自科学代表性不足的群体。研究的主要结果将被纳入本科课程和代表性不足群体的高中生的推广计划，并在科学家和利益相关者的地方和国家会议上提出。本地适应，即“本地”基因型在本地环境中相对于“外来”基因型的上级表现，是自然选择如何克服基因流动和漂移以塑造与环境相匹配的表型的有力证明。当地适应的经典测试是相互移植。然而，这样的实验往往无法捕捉移民过程中的关键方面，可能介导实现基因流在自然系统中。例如，相互移植实验通常在相同的生活史阶段（通常是成年）和相同的丰度或密度下测试本地和非本地表型，这并不能反映大多数物种实际上是如何扩散的。在真实的种群中，移民（非本地）的数量往往低于居民（本地），相对频率本身会影响适应度。特别是，罕见的表型可能会减少对资源的竞争，或从专门的病原体中相对释放。这种负频率依赖选择可以减少迁移者和当地居民因适应而产生的适应性差异，扩大有效基因流，从而保持更大的群体内遗传多样性。研究人员将联合收割机结合空间配对采样和精细尺度分子分析，将6个草甸深度梯度上的种子/幼苗性状变异与可能驱动这些模式的关键因素联系起来：当地环境条件、人口统计学和深度上的基因流。然后，该团队将在生态相关的背景下通过从不同深度种植种子并操纵与成年人和其他幼苗谱系相关的相对频率来实验测试交叉梯度传播的结果。当地的适应和频率依赖之间可能的相互作用是特别相关的大叶藻，这是最好的记录的遗传多样性和身份的生态效应的例子之一。此外，更好地了解海草性状差异不仅仅是一个学术兴趣问题，而是成功的海草恢复和保护的关键。该奖项反映了NSF的法定使命，并被认为值得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来支持。

项目成果

Intra-Meadow Variation in Seagrass Flowering Phenology Across Depths

不同深度海草开花物候的草甸内变化

• DOI: 10.1007/s12237-020-00814-0
• 发表时间: 2021
• 期刊: Estuaries and Coasts
• 影响因子: 2.7
• 作者: von Staats, Daniel A.;Hanley, Torrance C.;Hays, Cynthia G.;Madden, Sophia R.;Sotka, Erik E.;Hughes, A. Randall
• 通讯作者: Hughes, A. Randall

Local Adaptation in Marine Foundation Species at Microgeographic Scales

• DOI: 10.1086/714821
• 发表时间: 2021-08-01
• 期刊: BIOLOGICAL BULLETIN
• 影响因子: 1.6
• 作者: Hays, C. G.;Hanley, T. C.;Sotka, E. E.
• 通讯作者: Sotka, E. E.