US-Tunisia Planning Visit: The Genomics of Salinity Adaptation in the Medicago Truncatula-Sinorhizobium Symbiosis

0751073 Nuzhine这项提议是为了支持两位PIS，南加州大学洛杉矶分校分子与计算生物学系Sergey Nuzhdin博士和加州大学戴维斯分校进化与生态科Sharon Strauss博士计划访问突尼斯，以建立他们与突尼斯Hammam Lif Bordj Cedra生物技术中心Mohamed Elarabi Aouani博士之间的研究合作。PIS的合作还将有多名法国科学家与奥瓦尼博士合作。他们计划讨论元胞紫花苜蓿-中华根瘤菌共生中盐度适应的基因组学。他们将参加广泛的讨论，并参观突尼斯的实验室、温室设施和现场。Aouani博士的团队将在拟议的项目过程中贡献生物材料，执行基因表征和温室试验，并参与现场实验。智力优势：尽管达尔文强调生态相互作用对进化多样性的重要性，但我们最近才获得分子工具，使我们能够了解适应变化如何随着环境挑战和生态相互作用而进化。该项目将重点放在突尼斯生态多样性的元宝紫花苜蓿(MTR)及其固氮共生菌Sinorhizobium Meliloti(Sm)上。主要的研究目标是确定MTR和Sm基因组中参与适应和共同适应的基因网络，以响应高盐度条件。来自6个焦点种群的基因类型，其中3个来自高盐度地点，将在高盐度和低盐度条件下进行测试，并与来自高盐度和低盐度地点的根瘤菌菌株进行因子组合，以证明MTR基因和Sm基因在不同盐度条件下对性能的作用及其相互作用。同时的代谢组和转录组图谱将确定与实验处理之间的耐盐性和适应性权衡相关的基因网络。更广泛的影响：不断增加的土壤盐分是一个主要的农业问题，随着持续灌溉的进行，这个问题只会变得更加紧迫。该项目的一个长期目标是通过确定与耐盐性有关的遗传途径，并确定这些途径如何影响寄主植物与其固氮共生体的关系，促进适应盐碱环境的豆科作物的发展。由于世界上不同地区面临着相似的环境挑战，跨文化的知识交流和培训对于以科学为基础的问题解决至关重要。该项目将支持一名美国博士后科学家和一名美国研究生参加访问。

0751073 NuzhdinThis proposal is to support planning visits by the two PIs, Dr. Sergey Nuzhdin, Department of Molecular & Computational Biology, University of Southern California, Los Angeles and Dr. Sharon Strauss, Section of Evolution and Ecology, University of California at Davis, California to Tunisia, to establish research collaboration between them and Dr. Mohamed Elarabi Aouani, Center of Biotechnology, Technopole de Bordj Cedra (CBBC) in Hammam Lif, Tunisia. The PIs collaboration will also involve a number of French scientists working with Dr. Aouani. They plan to discuss the Genomics of Salinity Adaptation in the Medicago truncatula-Sinorhizobium symbiosis. They will participate in extensive discussions and tour the Tunisian lab, greenhouse facilities, and field sites. Dr. Aouani's team will contribute biological material, perform genetic characterization and greenhouse trials, and participate in field experiments during the course of the proposed project.Intellectual merit: Although Darwin emphasized the importance of ecological interactions for evolutionary diversification, we have only recently acquired the molecular tools that allow us to understand how adaptive variation evolves in response to environmental challenges and ecological interactions. The project will focus on an ecographically diverse Tunisian collection of Medicago truncatula (Mtr) and their nitrogen-fixing symbionts Sinorhizobium meliloti (Sm). The primary research goal is to identify networks of genes in the Mtr and Sm genomes that are involved in adaptation and coadaptation in response to high-salinity conditions. Genotypes from six focal populations, three from highly saline sites, will be tested under high vs. low salinity and in factorial combinations with rhizobial strains from high and low salinity sites, to document the roles of Mtr genotype, Sm genotype, and their interaction on performance under contrasting salinity regimes. Concurrent metabolome and transcriptome profiles will identify networks of genes associated with salinity tolerance and fitness tradeoffs between experimental treatments. Broader impacts: Increasing soil salinity is a major agricultural problem that will only becomemore urgent with continued irrigation. A long-term goal of this project is to facilitate thedevelopment of legume crops suited to saline environments, by identifying genetic pathways involved in salinity tolerance, and determining how these pathways influence the relationship of the host plant with its nitrogen-fixing symbiont. Because disparate regions of the world face similar environmental challenges, cross-cultural exchanges of knowledge and training are essential for science-based problem solving. The project will involve support for a U.S. post-doctoral scientist and a U.S. graduate student to participate in the visits.