RoL: RUI: Collaborative Research: Understanding the Ecological and Genomic Bases of Local Adaptation in an Obligate Pollination Mutualism

所有生物都必须管理来自其环境和与其他生物相互作用的压力。生物学家长期以来一直认为，与捕食者、竞争者和有益的互助者的互动是生命史上一股强大的力量，有助于刺激新物种的形成。然而，很难测试生物之间的相互作用是否比炎热、寒冷或干旱等物理环境的影响更重要。该项目通过利用生活在莫哈韦沙漠极端环境中的物种之间的独特互动来进行这种比较。约书亚树是莫哈韦山脉上发现的一种螺旋形、扭曲的树，没有丝兰蛾的帮助就不能结出果实。乔舒亚的树花似乎适应了飞蛾，但这些树也经历了极端的高温和干旱，这些物理的、非生物环境的影响似乎也影响了它们的生存。约书亚树基因组计划将使用基因测序和约书亚树苗的实验来研究这些树如何应对沙漠不同地区的不同气候。然后，项目合作者可以将气候对约书亚树种群的影响与它们与丝兰蛾相互作用的影响进行比较。该团队还将聘请莫哈韦地区的志愿者和科学教师来测量和监测自家后院的约书亚树种群。通过首次详细研究约书亚树对气候的适应，该项目将有助于回答地球生命史上一个长期存在的问题-生物之间的互动或物理环境之间的相互作用是否更重要-并开发科学工具和社区合作伙伴关系，以帮助保护约书亚树在未来气候变化的情况下。约书亚树基因组计划是由威拉米特大学、加州州立大学北岭分校、阿拉巴马大学和夏威夷大学以及美国地质调查局西部生态研究中心的生态学家、遗传学家、生物信息学家和植物生理学家合作完成的。合作者将在莫哈韦周围的公共花园地点种植约书亚树苗，监测它们的生长和生理表现，并使用RNA测序来识别在不同气候下差异表达的基因。该团队将完成约书亚树的参考基因组，并将其与基因表达结果一起用于设计序列捕获阵列，用于数百棵树的定向测序。定向测序将使他们能够对有助于普通花园中幼苗存活和表现的生理性状以及与丝兰蛾授粉有关的花卉性状进行全基因组关联研究(GWAS)。然后，该团队将使用景观基因组分析来识别表明当地适应气候和蛾子特征变化的基因。与此同时，该团队将扩大一个参与式科学项目，与莫哈韦地区保护非营利组织和K-12教育工作者合作，培训志愿者调查约书亚树木种群的人口统计学，记录有多少树木开花和结果，以及有多少幼树存在以更新种群。最后，该团队将使用他们的遗传分析结果来建立一个基因组预测协议，该协议可以仅根据遗传数据来预测约书亚树种群的生理和授粉相关特征。该团队将使用这一协议来预测志愿者调查地点的树木特性，并测试种群预测的特性值与其人口健康之间的关系。这将使他们能够识别在当前条件下影响约书亚树适合度的特定特征，并将提供一个工具来评估约书亚树种群在未来气候中的弹性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

All living things must manage stress from their environment and interactions with other living things. Biologists have long believed that interactions with predators, competitors, and helpful mutualists are a powerful force in the history of life, helping to spur the formation of new species. However, it is difficult to test whether interactions between living things have been more important than the effects of the physical environment like heat, freezing, or drought. This project makes that comparison by taking advantage of a unique interaction between species that live in the extreme environments of the Mojave Desert. Joshua trees, the spikey, twisted-looking trees found across the Mojave, cannot produce fruit without the help of yucca moths. Joshua tree flowers appear to be adapted to the moths, but the trees also experience extreme heat and drought, and it seems likely that these effects of the physical, nonliving environment also impact their survival. The Joshua Tree Genome Project will use genetic sequencing and experiments with Joshua tree seedlings to study how the trees cope with different climates in different parts of the desert. The project collaborators can then compare the effects of climate on Joshua tree populations to the effects of their interaction with yucca moths. The team will also engage volunteers and science teachers across the Mojave region to measure and monitor Joshua tree populations in their own backyards. By examining the Joshua tree's adaptation to climate in detail for the first time, this project will help to answer a longstanding question in the history of life on Earth — whether interactions between living things or the physical environment have been more important — and develop scientific tools and community partnerships that can help protect Joshua trees under changing future climates.The Joshua Tree Genome Project is a collaboration of ecologists, geneticists, bioinformaticians, and plant physiologists at Willamette University, California State University Northridge, the Universities of Alabama and Hawaii, and the US Geological Survey Western Ecological Research Center. The collaborators will plant Joshua tree seedlings at common-garden sites around the Mojave, monitor their growth and physiological performance, and use RNA sequencing to identify genes that are differentially expressed in different climates. The team will complete a Joshua tree reference genome and use it with the gene expression results to design a sequence capture array for targeted sequencing of hundreds of trees. Targeted sequencing will allow them to perform genome-wide association study (GWAS) of physiological traits that contribute to seedlings’ survival and performance in the common gardens, and of floral traits related to pollination by yucca moths. The team will then use landscape genomic analyses to identify genes showing signatures of local adaptation to variation in climate and moth traits. Meanwhile, the team will expand a participatory science program working with Mojave-regional conservation nonprofits and K-12 educators to train volunteers to survey the demography of Joshua tree populations, recording how many trees flower and produce fruit, and how many young trees are present to renew the population. Finally, the team will use the results of their genetic analyses to build a genomic prediction protocol that can project the physiological and pollination-related traits of a Joshua tree population from genetic data alone. The team will use this protocol to predict the traits of trees at sites profiled by volunteer surveys, and test for relationships between populations’ predicted trait values and their demographic health. This will allow them to identify specific traits that influence the fitness of Joshua trees in current conditions, and would provide a tool to assess the resilience of Joshua tree populations in future climates.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.