''Medicago truncatula'', the barrelclover, strong-spined medick, barrel medic, or barrel medick, is a small annual

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

native to the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

region that is used in

genomic Genomics is an interdisciplinary field of biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, three-dim ...

research. It is a low-growing,

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

-like plant tall with trifoliate

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

. Each leaflet is rounded, long, often with a dark spot in the center. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are yellow, produced singly or in a small

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

of two to five together; the

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is a small, spiny pod. This species is studied as a

model organism A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...

for legume biology because it has a small

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

, is self-fertile, has a rapid generation time and prolific seed production, is amenable to genetic

transformation Transformation may refer to: Science and mathematics In biology and medicine * Metamorphosis, the biological process of changing physical form after birth or hatching * Malignant transformation, the process of cells becoming cancerous * Trans ...

, and its genome has been sequenced. It forms symbioses with

nitrogen-fixing Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmos ...

rhizobia Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In gene ...

(''

Sinorhizobium meliloti ''Ensifer meliloti'' (formerly ''Rhizobium meliloti'' and ''Sinorhizobium meliloti'') are an aerobic, Gram-negative, and diazotrophic species of bacteria. ''S. meliloti'' are motile and possess a cluster of peritrichous flagella. ''S. meliloti'' ...

'' and '' Sinorhizobium medicae'') and

arbuscular mycorrhiza An arbuscular mycorrhiza (AM) (plural ''mycorrhizae'', a.k.a. ''endomycorrhiza'') is a type of mycorrhiza in which the symbiont fungus (''AM fungi'', or AMF) penetrates the cortical cells of the roots of a vascular plant forming arbuscules. (N ...

l fungi including ''

Rhizophagus irregularis ''Rhizophagus irregularis'' (previously known as ''Glomus intraradices'') is an arbuscular mycorrhizal fungus used as a soil inoculant in agriculture and horticulture. ''Rhizophagus irregularis'' is also commonly used in scientific studies of th ...

'' (previously known as ''

Glomus intraradices ''Rhizophagus irregularis'' (previously known as ''Glomus intraradices'') is an arbuscular mycorrhizal fungus used as a soil inoculant in agriculture and horticulture. ''Rhizophagus irregularis'' is also commonly used in scientific studies of the ...

''). The model plant ''

Arabidopsis thaliana ''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. ''A. thaliana'' is considered a weed; it is found along the shoulders of roads and in disturbed land. A winter a ...

'' does not form either symbiosis, making ''M. truncatula'' an important tool for studying these processes. It is also an important

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

crop species in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Sequencing of the genome

The draft sequence of the genome of ''M. truncatula'' cultivar A17 was published in the journal'' Nature'' in 2011. The

sequencing In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which succ ...

was carried out by an international partnership of research laboratories involving researchers from the

University of Oklahoma The University of Oklahoma (OU) is a Public university, public research university in Norman, Oklahoma. Founded in 1890, it had existed in Oklahoma Territory near Indian Territory for 17 years before the two Territories became the state of Oklahom ...

(US), J. Craig Venter Institute (US),

Genoscope The French National Sequencing Center (Genoscope) was created in 1996 in Évry, France. It has been involved in the sequencing of the human genome The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA withi ...

(France), and

Sanger Centre The Wellcome Sanger Institute, previously known as The Sanger Centre and Wellcome Trust Sanger Institute, is a non-profit British genomics and genetics research institute, primarily funded by the Wellcome Trust. It is located on the Wellcome Ge ...

(UK). Partner institutions included the

University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Tw ...

(US), University of California-Davis (US), the National Center for Genomic Resources (US),

John Innes Centre The John Innes Centre (JIC), located in Norwich, Norfolk, England, is an independent centre for research and training in plant and microbial science founded in 1910. It is a registered charity (No 223852) grant-aided by the Biotechnology and B ...

(UK), Institut National de Recherche Agronomique (France),

Munich Information Center for Protein Sequences The Munich Information Center for Protein Sequences (MIPS) was a research center hosted at the Institute for Bioinformatics (IBI) at Neuherberg, Germany with a focus on genome oriented bioinformatics, in particular on the systematic analysis of ge ...

(Germany),

Wageningen University Wageningen University & Research (also known as Wageningen UR; abbreviation: WUR) is a public university in Wageningen, Netherlands, specializing in life sciences with a focus on agriculture, technical and engineering subjects. It is a globally ...

(the Netherlands), and

Ghent University Ghent University ( nl, Universiteit Gent, abbreviated as UGent) is a public research university located in Ghent, Belgium. Established before the state of Belgium itself, the university was founded by the Dutch King William I in 1817, when the ...

(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 The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I ...

and the European Union 6th Framework Programme began providing most of the funding. By 2009, 84% of the genome assembly had been completed. The assembly of the genome sequence in ''M. truncatula'' was based on

bacterial artificial chromosome A bacterial artificial chromosome (BAC) is a DNA construct, based on a functional fertility plasmid (or F-plasmid), used for transforming and cloning in bacteria, usually '' E. coli''. F-plasmids play a crucial role because they contain partition ...

s (BACs). This is the same approach used to sequence the genomes of humans, the fruitfly, ''

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Ch ...

'', and the model plant, ''

''. In July 2013, version 4.0 of the genome was released. This version combined sequences gained from

shotgun sequencing In genetics, shotgun sequencing is a method used for sequencing random DNA strands. It is named by analogy with the rapidly expanding, quasi-random shot grouping of a shotgun. The Sanger sequencing#Method, chain-termination method of DNA sequencin ...

with the BAC-based sequence assemblies, which has helped to fill in the gaps in the previously 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.

Symbioses with soil microorganisms

Researcher Toby Kiers of VU University Amsterdam and associates used ''M. truncatula'' to study symbioses 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 fungi did pass along more of their phosphorus to the more generous plants.

Proteome

Proteomic investigation by

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is use ...

has been performed by Wienkoop et al 2004 and Larrainzar et al 2007.

References

External links

The ''Medicago truncatula'' Consortium''Medicago truncatula'' Hapmap ProjectTIGR's link to Genome Browser and Gene IndexThe 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
* *
NCGREuropean Research Programmes on the model legume Medicago truncatulaWhy sequence medicago truncatula?
{{Taxonbar, from=Q136894 Forages Flora naturalised in Australia Genomics truncatula Plant models Flora of Lebanon and Syria

Sequencing of the genome

Symbioses with soil microorganisms

Proteome

See also

References

Further reading

External links