NSF Postdoctoral Fellowship in Biology FY 2020: Quantifying nutrient sharing across mutualisms and identifying involved genetic factors

本行动资助2021财年美国国家科学基金会植物基因组生物学博士后研究奖学金。该奖学金支持奖学金获得者在主办实验室的研究和培训计划，该奖学金获得者还提出了扩大生物学参与的计划。因加·康蒂-杰佩博士的研究和培训计划的标题是“量化互惠关系中的营养共享并确定相关的遗传因素”。该奖学金的主办机构是加州大学伯克利分校，赞助科学家是丽贝卡·塔文博士和托德·道森博士。在共生关系中，两个物种交换营养物质，使双方都能获得辅助的营养资源，使它们能够在营养有限的条件下生存。例如，许多植物与土壤真菌共生，提供植物自身无法吸收的营养。作为交换，真菌接受植物通过光合作用产生的糖。这些类型的关系存在于其他生命形式中，包括与单细胞藻类有关的海洋无脊椎动物（珊瑚、水母、蛤蜊、海蛞蝓和扁虫），以及由藻类和真菌共同生活的地衣。通过结合它们的营养，这些伙伴在营养沙漠中茁壮成长，并为森林和珊瑚礁等关键生态系统提供基础。本研究将通过测量植物、海洋无脊椎动物和地衣的营养共享，以及识别与紧密和松散耦合伙伴相关的特征，来研究共生进化的模式。这将创建一个预测框架，在这个框架中，性状可以用来评估共生关系中营养交换的性质。此外，这项研究将操纵树木和真菌之间的共生模型，以确定支撑伙伴之间营养共享的基因。该项目范围广泛，适合本科生指导，他们将对所调查的许多共生伙伴关系之一进行独立研究。其他更广泛的影响包括每月定期举办一次讲习班，重点关注在科学领域支持和向妇女传授技能，以及制定和部署一项关于数据可视化和解释的高中课程计划。在多个分类群的共生关系中，相同的一组不同的特征已经进化出来：1)专性与兼性关系，2)细胞内与细胞外的联系，以及3)共生体的垂直与水平传播。这些特征被认为影响了共生伙伴之间的共同进化，然而，人们对它们如何影响全息生物内部的营养共享知之甚少。此外，调控这些共生适应的基因是未知的。该项目使用稳定同位素分析来量化共生生物之间的营养共享，这些共生生物表现出不同的特征，以验证一种假设，即维持垂直传输的专性细胞内伙伴之间的营养共享比依赖水平传输的同时性细胞外伙伴之间的营养共享更大。此外，本研究将利用转录组学来比较与丛枝菌根或外生菌根相关的白杨桤木（Alnus incana）的基因表达，并测试与细胞内相关伙伴相比，与细胞外相关伙伴共生时，参与营养转移的基因是否上调。稳定同位素数据将在Dryad数字存储库（https://datadryad.org/stash）和/或IsoBank （http://isobank.tacc.utexas.edu/en/）上提供。原始序列读取将在NCBI序列读取档案（https://www.ncbi.nlm.nih.gov/sra）中进行数字存档，比较转录组学数据也将在Dryad上存档。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。

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2021. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Dr. Inga Conti-Jerpe is "Quantifying nutrient sharing across mutualisms and identifying involved genetic factors". The host institution for the fellowship is the University of California, Berkeley and the sponsoring scientists are Dr. Rebecca Tarvin and Dr. Todd Dawson.Symbiotic relationships in which two species exchange nutrients afford both partners access to auxiliary nutritional resources, allowing them to survive under nutrient limited conditions. Many plants, for example, live in symbiosis with soil fungi that provide nutrients the plant cannot assimilate on its own. In exchange, the fungus receives sugars produced by the plant through photosynthesis. These types of relationships exist in other lifeforms including marine invertebrates (corals, jellyfish, clams, sea slugs, and flat worms) that associate with single-celled algae, and lichens, which are comprised of algae and fungi living together. By coupling their nutrition, these partners thrive in nutritional deserts and provide the foundation for critical ecosystems such as forests and coral reefs. This research will investigate patters in the evolution of symbioses by measuring nutrient sharing in plants, marine invertebrates, and lichens, and identifying traits associated with tightly and loosely coupled partners. This will create a predictive framework where traits can be used to assess the nature of nutritional exchange within a symbiotic relationship. Additionally, this research will manipulate a model symbiosis between trees and fungi to identify genes that underpin nutrient sharing between partners. The broad scope of this project lends itself to the mentorship of undergraduates who will conduct independent research on one of the many symbiotic partnerships investigated. Additional broader impacts are a regular, bimonthly workshop focused on supporting and transferring skills to women in science, as well as the development and deployment of a high school lesson plan on data visualization and interpretation.The same set of disparate traits have evolved in symbioses across multiple taxa: 1) obligate vs facultative relationships, 2) intracellular vs extracellular associations, and 3) vertical vs horizontal transmission of symbionts. These traits are thought to influence coevolution between symbiotic partners, however there is little understanding of how they affect nutrient sharing within the holobiont. Further, the genes that regulate these symbiotic adaptations are unknown. This project uses stable isotope analysis to quantify nutrient sharing across symbioses exhibiting disparate traits to test the hypothesis that nutrient sharing is greater between obligate, intracellular partners that maintain vertical transmission compared to facultative, extracellular partners that rely on horizontal transmission. Further, this work will use transcriptomics to compare gene expression in Alnus incana (grey alder) when associated with arbuscular mycorrhizae or ectomycorrhizae and test whether genes involved in nutrient transfer are upregulated in symbiosis with intracellularly associated partners compared to extracellularly associated partners. Stable isotope data will be available on the Dryad Digital Repository (https://datadryad.org/stash) and/or IsoBank (http://isobank.tacc.utexas.edu/en/). Raw sequence reads will be digitally archived with the NCBI Sequence Read Archive (https://www.ncbi.nlm.nih.gov/sra) and comparative transcriptomics data will also be archived on Dryad.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.