MCA: Using phylogenetic comparative methods to link plant-soil interactions, including with pathogens and mutualists, with physiological mechanisms across Rhododendron

植物与土壤微生物（包括病原体和共生菌）的相互作用对植物的健康、多样性、分布和丰度至关重要。这类研究大多缺少的是进化史和生理机制之间的联系。这项工作探讨了一种假设，即疾病耐受性部分是由对水的生理适应形成的，这种适应平衡了水保持和碳获取之间的基本权衡。因为像根腐病这样的疾病限制了对水的获取，对水分胁迫的生理适应可能对理解疾病耐受性至关重要。同样，地下共生菌的存在也可能通过生理机制介导疾病耐受性。为了探索这些问题，研究者将在不同的杜鹃花分类群中整合生理学和微生物方法。杜鹃属植物对一种入侵植物病原菌（Phytophthora cinnamomi）的易感性在物种间存在差异，因此杜鹃属植物是开展该研究的理想系统。肉桂疫霉引起根腐病，可感染5000多种植物。了解控制这种相互作用的机制可以改善对抗逆性和抗病性作物的选择。表征菌根真菌共生菌的有益作用也将提高园艺成果，包括为苗圃产业带来更健康的植物。该项目将为处于职业生涯中期的科学家提供学习新的生理和微生物学工具的机会，以应用于本项目和未来的项目。这项工作将促进PI的职业目标，即发展生理和机械研究计划，加深对植物-土壤相互作用的理解，向晋升教授迈进，并培养一个多样化的生态学和生理学实验室。PI和合作者将为不同的研究生和本科生研究人员提供培训。招聘工作将利用现有的项目，如麦克奈尔学者和凯斯西储大学的北极星联盟。该研究员将进行普通的花园和温室实验，以探索疾病易感性的生理和系统发育决定因素。在实验水梯度上种植20种杜鹃花将提供一种测试，以确定对水胁迫的反应是否由进化史决定。温室试验将测试生理机制如何影响病原体耐受性。另一项实验将探索菌根共生菌如何改变生理性状和疾病易感性。这项中期职业晋升奖还将培训PI掌握尖端的植物生理学技术，包括浮肿损失点的测量，将培训一名植物生理学和生态学研究生，并将为本科生研究人员提供培训机会。这项工作还将包括开发一个开放获取数据库RA-LEAFY，以利用热情的杜鹃花和杜鹃花爱好者组成的庞大社区，并为不同的学生和社区成员创造科学参与的机会。这项工作为科学研究提供了一个可进入的切入点，将加强对各类人才的招聘。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。

Plant interactions with soil microbes, including pathogens and mutualists, are critical for plant health, diversity, distribution, and abundance. Missing from much of this research is the link between evolutionary history and physiological mechanisms. This work explores the hypothesis that disease tolerance has been shaped in part by physiological adaptations to water, which balance fundamental tradeoffs between water retention and carbon acquisition. Because diseases like root rot limit access to water, physiological adaptations to water stress may be essential to understanding disease tolerance. Similarly, the presence of belowground mutualists may also mediate disease tolerance through physiological mechanisms. To explore these issues, the investigator will integrate physiological and microbial approaches across diverse Rhododendron taxa. Rhododendron provide an ideal system to conduct this research because of the variation among species in disease susceptibility to an invasive plant pathogen (Phytophthora cinnamomi). Phytophthora cinnamomi causes root rot disease and can infect over 5000 plant species. Understanding the mechanisms governing this interaction can improve selection for stress and disease tolerant crops. Characterizing the beneficial effects of mycorrhizal fungal mutualists also will enhance horticultural outcomes, including leading to healthier plants for the nursery industry. The project will give a mid-career scientist the opportunity to learn new physiological and microbiological tools to be applied to this and future projects. This work will enhance the PI’s career goals of developing a physiological and mechanistic program of study, deepening the understanding of plant-soil interactions, progressing toward promotion to Professor, and training a diverse lab in ecology and physiology. The PI and collaborators will provide training for diverse graduate and undergraduate researchers. Recruitment efforts will leverage existing programs such as the McNair Scholars and the North Star Consortium at Case Western Reserve University.This investigator will conduct common garden and greenhouse experiments to explore the physiological and phylogenetic determinants of disease susceptibility. Growing 20 Rhododendron species across an experimental water gradient will provide a test of whether responses to water stress are shaped by evolutionary history. A greenhouse experiment will test how physiological mechanisms influence pathogen tolerance. Another experiment will explore how mycorrhizal mutualists modify physiological traits and disease susceptibility. This mid-career advancement award will also train the PI in cutting edge plant physiological techniques, including the measurement of turgor loss point, will train a graduate student in plant physiology and ecology, and will provide training opportunities for undergraduate researchers. This work will also include the development of an open access database, RA-LEAFY, to tap into the considerable community of enthusiastic Rhododendron and Azalea hobbyists and generate opportunities for scientific engagement for diverse students and community members. By providing an accessible entry point into scientific research, this work will enhance recruitment of diverse talent to the scientific workforce.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.