Free amino acid profiles suggest a possible role for asparagine in the control of storage-product accumulation in developing seeds of low- and high-protein soybean lines

Cinta Hernández-Sebastià, Frédéric Marsolais, Carole Saravitz, Dan Israel, Ralph E. Dewey, Steven C. Huber

Research output: Contribution to journalArticlepeer-review

Abstract

Several approaches were taken to examine the role of N-assimilate supply in the control of soybean (Glycine max) seed composition. In the first study, developing seeds were grown in vitro with D-[U-14C]sucrose (Suc) and different concentrations of Gln. Light stimulated carbon flux into oil and protein, and was required to sustain Sue uptake and anabolic processes under conditions of elevated nitrogen supply. High Gln supply resulted in higher transcript levels of β-conglycinin and oleosin. In the second study, analyses of soluble amino acid pools in two genetically related lines, NC103 and NC106 (low- and high-seed protein, respectively) showed that, in the light, NC106 accumulated higher levels of Asn and several other amino acids in developing cotyledons compared with NC103, whereas at the seed coat and apoplast levels both lines were similar. In the dark, NC103 accumulated Gln, Arg, and its precursors, suggesting a reduced availability of organic acids required for amino acid interconversions, while NC106 maintained higher levels of the pyruvate-derived amino acids Val, Leu, and Ile. Comparing NC103 and NC106, differences in seed composition were reflected in steady-state transcript levels of storage proteins and the lipogenic enzyme multi-subunit acetyl CoA carboxylase. In the third study, a positive correlation (P ≤0.05) between free Asn in developing cotyledons and seed protein content at maturity was confirmed in a comparison of five unrelated field-grown cultivars. The findings support the hypothesis that high seed-protein content in soybean is determined by the capacity of the embryo to take up nitrogen sources and to synthesize storage proteins. Asn levels are probably tightly regulated in the embryo of high-protein lines, and may act as a metabolic signal of seed nitrogen status.

Original languageEnglish (US)
Pages (from-to)1951-1963
Number of pages13
JournalJournal of experimental botany
Volume56
Issue number417
DOIs
StatePublished - Jul 2005

Keywords

  • Amino acid profile
  • Carbon partitioning
  • Seed nitrogen supply
  • Seed protein content
  • Soybean

ASJC Scopus subject areas

  • Physiology
  • Plant Science

Fingerprint

Dive into the research topics of 'Free amino acid profiles suggest a possible role for asparagine in the control of storage-product accumulation in developing seeds of low- and high-protein soybean lines'. Together they form a unique fingerprint.

Cite this