Community Genomics of Local Adaptation in Medicago Truncatula

University Of Southern California, Los Angeles CA

Investigators

Abstract

PI: Sergey Nuzhdin, University of Southern California Co-PI: Eric von Wettberg, University of California, Davis Legume plants, including the agriculturally important species soybean, alfalfa, pea, and bean, collaborate with rhizobium bacteria to convert atmospheric nitrogen to biologically available ammonia. This property has enabled legumes to colonize marginal habitats and provides an ideal system to study how coevolution promotes adaptation to stressful environments. The model legume Medicago truncatula is a close relative of alfalfa and grows naturally in both highly saline soils across North Africa as well as on normal soils. In collaboration with Tunisian and French researchers, this research project will use genomic resources to understand how Medicago and its partner Sinorhizobium have adapted to saline soil. The main goal of this research is to identify both the genes and the genetic and biochemcial networks that underlie ecological differences between saline-adapted and non-adapted populations. By measuring the effects of these genes and networks under the natural conditions that plants experience, this research has the unique potential to bridge genetics, ecology, and evolution. Statement broader impacts Soil salinisation is a growing problem with the potential to impact up to one third of agricultural land world-wide. Thus, understanding how abiotic factors, including salinity, impact symbiotic efficiency represents an important challenge for agriculture both in the developed and developing world. Since Medicago truncatula is a model species, the genes and pathways identified in this research will be directly applicable to breeding efforts to improve many agriculturally important legumes and more broadly to plant biology as a whole. The interdisciplinary and inter-continental nature of this project further provides an exceptional training opportunity. This project will integrate Tunisian and American teams-facilitated by generous matching funds from public (UC Davis) and private (USC) institutions-by cooperatively performing field experiments in Tunisia and through the exchange of personnel. Tunisian students and scholars will be hosted at the US institutions where they will engage in research, undertake individually-tailored coursework, and make contacts that will spur their professional growth. American undergraduate and graduate students will benefit via hands-on research experience, individual mentored projects, and the opportunity to participate in workshops and conferences in North Africa. All data generated by this research will be made publicly available at http://nlab.usc.edu. The project website will be publicly accessible with released data and project updates. The genotyping array, and the genotype and phenotype data collected will serve as a community resource enabling future work on Medicago. The results of this research will be published in peer-reviewed open-access journals, made accessible to the American and African media, and presented by junior members of the team at international meetings across the globe.