CAREER: Drivers of Plant-Microbe Symbiosis Evolution During Crop Domestication

职业：作物驯化过程中植物-微生物共生进化的驱动因素

• 批准号: 1943239
• 负责人: Stephanie Porter
• 金额: $ 99.99万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1943239&HistoricalAwards=false
• 关键词: CAREER; Drivers; Plant; Microbe; Symbiosis

Over thousands of years of domestication and crop improvement, humans have shaped hundreds of wild plant species into the diverse crops we depend upon. While beneficial microbes that live on and inside of plants play key roles in plant health, little is known about how a plants’ ability to benefit from these cooperative microbes changes during domestication. Plant-microbe cooperation is not stable. In fact, plants have repeatedly abandoned cooperation with microbes over evolutionary time, and growing evidence shows that some crops evolve to depend less on microbes over the course of domestication. This reveals a gap in our understanding of the evolution of cooperation: what evolutionary processes result in abandoning cooperation? And why does cooperation with microbes decline for some plant species, but not others? To investigate how these symbiotic relationships differ between modern crops and their wild relatives, this project will use seed collections and genomic resources for legume crops ranging from soybeans to peas. The utility of legumes in agriculture lies in their unique symbiosis with rhizobial bacteria, which convert atmospheric nitrogen into chemical forms usable to plants, essentially fertilizing them. At least forty-one legume species have been domesticated. Researchers will compare domesticated legumes’ ability to benefit from rhizobia to that of their wild relatives by using modern genetic and analytical approaches. These techniques will provide insight into how natural selection has changed patterns of cooperation between legumes and rhizobia during domestication. Legumes account for a quarter of global crop production and a third of human dietary protein. Understanding how and why rhizobial symbiosis has evolved during domestication will provide a critical road map for ways in which we could improve crop yield in order to increase our ability to feed our growing human population. Crop domestication is also a tangible example of evolution in action--domesticated species have provided an intuitive model for evolutionary biology since Darwin’s original arguments. Project research will engage undergraduates with evolutionary problems in familiar food crops. To increase the inclusion of underrepresented minority and community college transfer students in science, the researchers will develop a new Course-based Undergraduate Research Experience (CURE) module on symbiosis and crop domestication and a new Science Scholars Program to recruit and retain diverse undergraduates in scientific research.A paradigm shift in the field of mutualism evolution is a newfound appreciation for the frequency with which host organisms, such as plants, have abandoned mutualisms with symbiotic microbiota. Yet, little is known about the micro-evolutionary processes that lead to declines in host symbiosis traits. This project will use germplasm and genomic resources that exist for legume crops as a powerful system with which to investigate declines in plant symbiosis traits over replicated evolutionary lineages from wild plants to modern elite cultivars. By integrating approaches from phylogenetics, molecular genetics, quantitative genetics, and genomics, this project will contribute fundamental knowledge about the role of trade-offs, natural selection, and genetic costs in shaping micro-evolutionary dynamics in symbiotic mutualism. To elucidate the traits, forms of selection, and loci that underlie changes in legume-rhizobium symbiosis across thousands of years of evolution in agriculture, researchers will: 1) quantify how the nitrogen-fixing symbiosis with rhizobia differs between leguminous crops and their wild relatives, 2) test whether legume symbiosis traits have negative genetic correlations with legume traits favored under artificial selection, 3) test whether fertilization relaxes selection on legume symbiosis traits or selects for reduced symbiosis, and 4) infer whether genetic costs of domestication are predicted to degrade symbiosis traits in crops. This work will pave the way towards integrating an understanding of the evolutionary forces and constraints that underlie dynamics between hosts and microbial symbionts into the mainstream of evolutionary biology.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.

经过数千年的驯化和作物改良，人类已经将数百种野生植物物种塑造成我们所依赖的各种作物。虽然生活在植物表面和内部的有益微生物在植物健康中起着关键作用，但人们对植物在驯化过程中如何从这些合作微生物中获益的能力知之甚少。植物-微生物合作并不稳定。事实上，在进化过程中，植物一再放弃与微生物的合作，越来越多的证据表明，一些作物在驯化过程中逐渐减少对微生物的依赖。这揭示了我们对合作进化的理解中的一个差距：什么样的进化过程导致了放弃合作？为什么某些植物物种与微生物的合作减少了，而其他物种却没有？为了研究这些共生关系在现代作物和它们的野生亲戚之间的差异，该项目将使用从大豆到豌豆的豆类作物的种子收集和基因组资源。豆科植物在农业中的用途在于它们与根瘤菌的独特共生关系，根瘤菌将大气中的氮转化为植物可用的化学形式，基本上是使植物生长。至少有41种豆科植物被驯化。研究人员将通过使用现代遗传和分析方法，比较驯化豆类与其野生亲戚从根瘤菌中获益的能力。这些技术将提供洞察自然选择如何改变豆科植物和根瘤菌在驯化过程中的合作模式。豆类占全球作物产量的四分之一，占人类膳食蛋白质的三分之一。了解根瘤菌共生在驯化过程中是如何以及为什么进化的，将为我们提高作物产量以提高我们养活不断增长的人口的能力提供一个关键的路线图。农作物驯化也是进化在起作用的一个具体例子--自达尔文最初的论点以来，驯化的物种为进化生物学提供了一个直观的模型。项目研究将使本科生参与熟悉的粮食作物的进化问题。为了增加在科学中代表性不足的少数民族和社区大学转学生的参与，研究人员将开发一个新的基于课程的本科生研究经验（CURE）模块，关于共生和作物驯化，以及一个新的科学学者计划，以招募和留住不同的本科生进行科学研究。例如植物，已经放弃了与共生微生物群的互惠关系。然而，我们对导致宿主共生特征下降的微进化过程知之甚少。该项目将利用豆科作物的种质和基因组资源作为一个强大的系统，研究从野生植物到现代优良品种的复制进化谱系中植物共生性状的下降。通过整合遗传学、分子遗传学、数量遗传学和基因组学的方法，该项目将有助于了解权衡、自然选择和遗传成本在共生互惠中塑造微观进化动力学的作用。为了阐明数千年农业进化中豆类-根瘤菌共生变化的特征，选择形式和位点，研究人员将：1）量化豆科作物与其野生近缘种之间与根瘤菌的固氮共生关系如何不同，2）测试豆科植物共生性状与人工选择下有利的豆科植物性状是否具有负遗传相关，3）测试施肥是否放松对豆类共生性状的选择或选择减少的共生，以及4）推断驯化的遗传成本是否被预测为降低作物中的共生性状。这项工作将为将宿主和微生物共生体之间动力学的进化力量和制约因素的理解整合到进化生物学的主流中铺平道路。该奖项反映了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。

项目成果

Impacts of domestication on the rhizobial mutualism of five legumes across a gradient of nitrogen-fertilisation

• DOI: 10.1007/s11104-023-06128-x
• 发表时间: 2023-07
• 期刊: Plant and Soil
• 影响因子: 4.9
• 作者: Niall Millar;J. Piovia‐Scott;S. Porter