Development and composition of the seeds of nine genotypes of the Medicago truncatula species complex.
The seed development and composition of Medicago truncatula Gaertn., the new model plant for grain legumes, was studied using nine genotypes of the species complex: M. truncatula-Medicago littoralis (M. truncatula). The seed development of M. truncatula was very similar to that of other legumes, the only notable exception being the presence, in the mature seed, of an endosperm layer that is absent in grain legumes. During early embryogenesis and until mid-maturation, transient storage of starch occurred in the seed coat and embryo. This temporary storage probably contributed to the early development of the embryo and reserve synthesis. During maturation the synthesis and accumulation of proteins and oil took place at quasi-constant rates. Conversely oligosaccharides, mainly stachyose, were synthesised only during late maturation and at the beginning of desiccation. Proteins represented the major class of storage compounds and their average amino acid composition was found to be very close to that of pea and robust in various environmental conditions. Similar compositions between the two species and other grain legumes were also found for the fatty acids and the soluble sugars; most of these characters varied depending on the various environmental conditions used for seed production. All these similarities fully justify the use of M. truncatula as a model plant for genomic approaches to grain legume improvement. The major difference between M. truncatula seeds and European grain legume seeds resides in the nature of their carbon storage namely triacylglycerides for M. truncatula and starch for pea and faba bean.
Djemel
Nadia
N
Laboratoire de Biologie des Semences, UMR 204 Inra/Ina-PG, Institut Jean-Pierre Bourgin, Inra, RD10, 78026 Versailles cedex, France.
Guedon
Delphine
D
Lechevalier
Arnaud
A
Salon
Christophe
C
Miquel
Martine
M
Prosperi
Jean-Marie
JM
Rochat
Christine
C
Boutin
Jean-Pierre
JP
D000596:Amino Acids / Q000096:biosynthesis; D005227:Fatty Acids / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D046913:Medicago truncatula / Q000254:growth & development* / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis; D009844:Oligosaccharides / Q000096:biosynthesis; D010940:Plant Proteins / Q000378:metabolism; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism; D013213:Starch / Q000096:biosynthesis
D000596:Amino Acids; D005227:Fatty Acids; D009844:Oligosaccharides; D010940:Plant Proteins; D013213:Starch; D009584:Nitrogen