FREE AMINO-ACID AND STORAGE PROTEIN-COMPOSITION OF SOYBEAN FRUIT EXPLANTS AND ISOLATED COTYLEDONS CULTURED WITH AND WITHOUT METHIONINE

Authors
Citation
Acg. Horta et L. Sodek, FREE AMINO-ACID AND STORAGE PROTEIN-COMPOSITION OF SOYBEAN FRUIT EXPLANTS AND ISOLATED COTYLEDONS CULTURED WITH AND WITHOUT METHIONINE, Annals of botany, 79(5), 1997, pp. 547-552
Citations number
21
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
03057364
Volume
79
Issue
5
Year of publication
1997
Pages
547 - 552
Database
ISI
SICI code
0305-7364(1997)79:5<547:FAASPO>2.0.ZU;2-C
Abstract
The in vitro culture of immature soybean cotyledons (in direct contact with the medium) and immature fruit explants (stem dipping into the m edium) on a defined medium containing glutamine and sulphate as sole s ources of N and S for 7 d led to rates of growth and reserve protein a ccumulation close to, or greater than, those occurring in situ. Supple mentation of the medium with 8.4 mM methionine had little effect on gr owth and protein accumulation. of the cotyledons in the explant system , but did result in significant increases in the isolated cotyledon sy stem. Methionine suppressed the synthesis of the 7S beta-subunit in bo th systems. The free amino pool of the cotyledons increased more than three-fold when methionine was present in the explant medium. In the i solated cotyledon system, the basal medium alone caused a large increa se (over 30-fold) in the free amino acid fraction, but methionine resu lted in an even greater increase (over 50-fold). In both systems the e xpansion involved a very large increase in the methionine pool, but ma ny other amino acids also showed large increases. Specific effects of methionine on individual amino acids were more clear in the explant sy stem, where its presence resulted in marked increases in serine, alani ne and asparagine. The data show that an abnormal situation arises on feeding with methionine, a fact to be considered before attributing ef fects on growth and protein synthesis directly to methionine. (C) 1997 Annals of Botany Company.