| Medicago truncatula | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Tribe: | Trifolieae |
| Genus: | Medicago |
| Species: | M. truncatula |
| Binomial name | |
| Medicago truncatula Gaertn. |
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Medicago truncatula (Barrel Medic or Barrel Medick or Barrel Clover) is a small 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. 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. The nodule formation is apparently dependent on the flavonoids pathway.[1]
It is also an important forage crop species in Australia.
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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. As of 2009, 84% of the genome assembly has been completed.[2]
Sequencing in Medicago truncatula is based on bacterial artificial chromosomes. This is the same approach used to sequence the genomes of humans, the 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.
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.[3]
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