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United States Department of Agriculture

Agricultural Research Service


Location: Corn Insects and Crop Genetics Research

Title: The medicago genome provides insight into evolution of rhizobial symbiosis)

item Young, Nevin
item Debelle, Frederic
item Oldroyd, Giles
item Geurts, Rene
item Cannon, Steven
item Mayer, Klaus
item Gouzy, Jerome
item Van de peer, Yves
item Schoof, Heiko
item Udvardi, Michael
item Cook, Douglas
item Meyers, Blake
item Spannagl, Manuel
item Cheung, Foo
item De mita, Stephane
item Proost, Sebastian
item Krishnakumar, Vivek
item Gundlach, Heidrun
item Zhou, Shinguo
item Mudge, Joann
item Bharti, Arvind
item Benedito, Vagner
item Murray, Jeremy
item Naoumkina, Marina
item Rosen, Benjamin
item Silverstein, Kevin
item Tang, Haibao
item Rombauts, Stephane
item Zhao, Patrick
item Zhou, Peng
item Barbe, Valerie
item Bardou, Philippe
item Bechner, Michael
item Bellec, Arnaud
item Berger, Anne
item Berges, Helene
item Bidwell, Shelby
item Bisseling, Ton
item Choisne, Nathalie
item Couloux, Arnaud
item Denny, Roxanne
item Deshpande, Shweta
item Doyle, Jeffrey
item Dudez, Anne-marie
item Farmer, Andrew
item Fouteau, Stephanie
item Franken, Carolien
item Gibelin, Chrystel
item Gish, John
item Gonzalez, Alvaro
item Green, Pamela
item Hallab, Asis
item Hartog, Marijke
item Hua, Axin
item Humphray, Sean
item Jeong, Dong-hoon
item Jing, Yi
item Jocker, Anika
item Kenton, Steve
item Kim, Dong-jin
item Klee, Kathrin
item Lai, Hongshing
item Lang, Chunting
item Lin, Shaoping
item Macmill, Simone
item Magdelenat, Ghislaine
item Matthews, Lucy
item Mccorrison, Jamison
item Monaghan, Erin
item Mun, Jeong-hwan
item Najar, Fares
item Nicholson, Christine
item Noirot, Celine
item Paule, Charles
item Poulain, Julie
item Prion, Florent
item Qin, Baifang
item Qu, Chunmei
item Retzel, Ernest
item Riddle, Clare
item Sallet, Erika
item Samain, Sylvie
item Samson, Nicolas
item Saurat, Olivier
item Scarpelli, Claude
item Schiex, Thomas
item Segurens, Beatrice
item Seigfried, Majesta
item Severin, Andrew
item Sherrier, Janine
item Shi, Ruihua
item Sims, Sarah
item Sinharoy, Senjuti
item Sterck, Lieven
item Vasylenko, Iryna
item Viollet, Agnes
item Wang, Keqin
item Wang, Bing-bing
item Wang, Xiaohong

Submitted to: Nature
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/13/2011
Publication Date: 11/16/2011
Citation: Young, N.D., Debelle, F., Oldroyd, G., Geurts, R., Cannon, S.B., Mayer, K.F., Gouzy, J., Van De Peer, Y., Schoof, H., Udvardi, M.K., Cook, D.R., Meyers, B.C., Spannagl, M., Cheung, F., De Mita, S., Proost, S., Krishnakumar, V., Gundlach, H., Zhou, S., Mudge, J., Bharti, A.K., Benedito, V.A., Murray, J.D., Naoumkina, M.A., Rosen, B., Silverstein, K.A., Tang, H., Rombauts, S., Zhao, P.X., Zhou, P., Barbe, V., Bardou, P., Bechner, M., Bellec, A., Berger, A., Berges, H., Bidwell, S., Bisseling, T., Choisne, N., Couloux, A., Denny, R., Deshpande, S., Doyle, J.J., Dudez, A., Farmer, A.D., Fouteau, S., Franken, C., Gibelin, C., Gish, J., Gonzalez, A.J., Green, P.J., Hallab, A., Hartog, M., Hua, A., Humphray, S., Jeong, D., Jing, Y., Jocker, A., Kenton, S.M., Kim, D., Klee, K., Lai, H., Lang, C., Lin, S., Macmill, S.L., Magdelenat, G., Matthews, L., Mccorrison, J., Monaghan, E.L., Mun, J., Najar, F.Z., Nicholson, C., Noirot, C., Paule, C.R., Poulain, J., Prion, F., Qin, B., Qu, C., Retzel, E.F., Riddle, C., Sallet, E., Samain, S., Samson, N., Saurat, O., Scarpelli, C., Schiex, T., Segurens, B., Seigfried, M., Severin, A., Sherrier, J.D., Shi, R., Sims, S., Sinharoy, S., Sterck, L., Vasylenko, I., Viollet, A., Wang, K., Wang, B., Wang, X. 2011. The medicago genome provides insight into evolution of rhizobial symbiosis. Nature. 480(7378):520-524.

Interpretive Summary: Many crop species have characteristics that make them difficult to use in experiments about fundamental questions in plant biochemistry, genetics, physiology, or development. "Model" species are used to partially bypass these difficulties and general findings about the models are then applied to other related crop species. Medicago truncatula, a close relative of alfalfa and a more distant relative of soybean and other beans, is used as a model because of characteristics such as its small size, short generation time, and relatively simple genetics. Medicago also shares, with many other species in the legume plant family, an association with "rhizobial" bacteria that are able to convert inert atmospheric nitrogen into a form of nitrogen fertilizer that the plants can use. This capacity, called nitrogen fixation, is extremely valuable in crop plants, because these species don't need supplemental nitrogen fertilizer. This paper reports the essentially complete genome sequence (the set of all DNA letters in the chromosomes) of M. truncatula. Analysis of the genome sequence and the contained genes shows that although the M. truncatula genome is less than half the size of the soybean genome and has not undergone a genome-doubling experienced by soybean, it nevertheless has nearly as many genes as soybean, and has accumulated more changes (large and small) since the two species diverged from their common ancestor. Analysis of genes involved in nitrogen fixation shows that this capacity probably evolved from older genes that were involved in plant-fungal interactions, and that the evolution was spurred by a genome doubling that occurred near the origin of the legume family, around 60 million years ago. The genome sequence and other findings are expected to have large impacts on crop plants in the legume family. The basic knowledge from M. truncatula may help plant breeders and biotechnologists develop crop varieties that are able to more efficiently "fix" and use their own nitrogen fertilizer.

Technical Abstract: Medicago truncatula is an excellent model for the study of legume-specific biology, especially endosymbiotic interactions with bacteria and fungi. This paper describes the sequence of the euchromatic portion of the M. truncatula genome based on a recently completed BAC-based assembly supplemented by Illumina-shotgun sequence, together capturing ~94% of all M. truncatula genes. A whole-genome duplication (WGD) that occurred approximately 58 million years ago contributed significantly to the genome we see today and supported the evolution of nodulation and symbiotic nitrogen fixation. Compared to soybean or Lotus japonicus, the M. truncatula genome experienced higher levels of genome rearrangement subsequent to the WGD. Our work provides evidence that this WGD and perhaps also a more ancient whole genome triploidization event gave rise to key components in the perception of rhizobial signals and formation of nitrogen fixing nodules, traits instrumental to the success of legumes and major drivers for their importance in natural and agricultural systems.

Last Modified: 8/24/2016
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