Medicago truncatula

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Medicago truncatula (Barrel Medic or Barrel Medick or Barrel Clover) is a small legume native to the Mediterranean region. It is a low-growing clover-like plant 10–60 cm tall with trifoliate leaves, each leaflet 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.

M. truncatula has been chosen as a model organism for legume biology. It has a small diploid genome, is self-fertile, has a rapid generation time and prolific seed production, and is also amenable to genetic transformation. The genome of M. truncatula is currently being sequenced.

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.

It is also an important forage crop species in Australia.

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. Legumes are a family of plants, including soybean, alfalfa and bean, which form ecologically important symbioses with bacteria (rhizobia) and fungi (mycorrhiza). Knowing the sequence of 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 frequently used as 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. The majority of the gene-containing portion of the Medicago truncatula genome is expected to be complete by the end of 2008.

Sequencing in Medicago truncatula is based on bacterial artificial chromosomes. This is the same approach used in human and in a small number of reference genomes like fruitfly, Drosophila melanogaster, and the model plant, Arabidopsis thaliana. The technique is slower, but typically more accurate, than the now more common approach known as Shotgun sequencing.

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.