||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (June 2009)|
Medicago tribuloides Desr.
Medicago truncatula (Barrel Medic or Barrel Medick or Barrel Clover) is a small annual legume native to the Mediterranean region that is used in genomic research. It is a low-growing, clover-like plant 10–60 cm tall with trifoliate leaves. Each leaflet is rounded, 1–2 cm long, often with a dark spot in the center. The flowers are yellow, produced singly or in a small inflorescence of 2-5 together; the fruit is a small spiny pod.
This species has been chosen as a model organism for legume biology because it has a small diploid genome, is self-fertile, has a rapid generation time and prolific seed production, and is amenable to genetic transformation.
It forms symbioses with nitrogen-fixing rhizobia (Sinorhizobium meliloti and Sinorhizobium medicae) and arbuscular mycorrhizal fungi. The model plant Arabidopsis thaliana does not form either symbiosis, making M. truncatula an important tool for studying these processes.
Medicago truncatula Sequencing Consortium
The Medicago truncatula Sequencing Consortium is an international partnership of research laboratories that is decoding the genome sequence of Medicago truncatula, a model legume species. Sequencing the Medicago truncatula genome is expected to facilitate genomics research in legumes, especially the biology of symbiosis because Medicago truncatula and its symbiotic partner, Sinorhizobium meliloti, are popular models for symbiosis research.
Sequencing in Medicago truncatula is taking place at the University of Oklahoma (US), J. Craig Venter Institute (US), Genoscope (France), and Sanger Centre (UK). Partner institutions include the University of Minnesota (US), University of California-Davis (US), the National Center for Genomic Resources (NCGR) (US), John Innes Centre (UK), Institut National de Recherche Agronomique (France), Munich Information Center for Protein Sequences (MIPS) (Germany), Wageningen University (Netherlands), and Ghent University (Belgium). The Medicago truncatula Sequencing Consortium began in 2001 with a seed grant from the Samuel Roberts Noble Foundation. In 2003, the National Science Foundation and the European Union 6th Framework Programme began providing most of the funding. By 2009, 84% of the genome assembly has been completed.
Sequencing in Medicago truncatula is based on bacterial artificial chromosomes or BACs. This is the same approach used to sequence the genomes of humans, the fruitfly, Drosophila melanogaster, and the model plant, Arabidopsis thaliana. The draft sequence of the genome of M. truncatula cultivar A17 was published in the journal Nature in 2011. In July 2013 version 4.0 of the genome was released. This version combines shotgun sequencing sequences with the BAC-based sequence assemblies, which has helped fill in the gaps in the mapped sequences.
A parallel group known as the International Medicago Gene Annotation Group (IMGAG) is responsible for identifying and describing putative gene sequences within the genome sequence.
Researcher Toby Kiers of VU University Amsterdam and associates used Medicago truncatula to study mutualisms between plants and fungi - and to see whether the partners in the relationship could distinguish between good and bad traders/suppliers. By using labeled carbon to track the source of nutrient flowing through the arbuscular mycorrhizal system, The researchers have proven that the plants had indeed given more carbon to the more generous fungus species. By restricting the amount of carbon the plants gave to the fungus, the researchers also demonstrated that the fungus did pass along more of their phosphorus to the more generous plants.
- Young et al (2011). The Medicago genome provides insight into the evolution of rhizobial symbioses, Nature. 
- The Medicago truncatula Consortium
- Medicago truncatula Hapmap Project
- TIGR's link to Genome Browser and Gene Index
- The Medicago Gene Expression Atlas at Samuel Roberts Noble Foundation
- Medicago truncatula eFP Browser Viewer for gene expression data from the Medicago Gene Expression Atlas project, at the Provart Lab's Bio-Array Resource website
- INRA Medicago truncatula Stock Center - France
Cannon et al. (2006) Proceedings National Academy Sciences USA, 103:14959-14964.
Young et al. (2005) Plant Physiology 137: 1174-1181.
|Wikispecies has information related to: Medicago truncatula|