Transgenic soybean plants overexpressing O-acetylserine sulfhydrylase accumulate enhanced levels of cysteine and Bowman-Birk protease inhibitor in seeds

Won Seok Kim, Demosthenis Chronis, Matthew Juergens, Amy C. Schroeder, Seung Won Hyun, Joseph M. Jez, Hari B. Krishnan

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Soybeans provide an excellent source of protein in animal feed. Soybean protein quality can be enhanced by increasing the concentration of sulfur-containing amino acids. Previous attempts to increase the concentration of sulfur-containing amino acids through the expression of heterologous proteins have met with limited success. Here, we report a successful strategy to increase the cysteine content of soybean seed through the overexpression of a key sulfur assimilatory enzyme. We have generated several transgenic soybean plants that overexpress a cytosolic isoform of O-acetylserine sulfhydrylase (OASS). These transgenic soybean plants exhibit a four- to tenfold increase in OASS activity when compared with non-transformed wild-type. The OASS activity in the transgenic soybeans was significantly higher at all the stages of seed development. Unlike the non-transformed soybean plants, there was no marked decrease in the OASS activity even at later stages of seed development. Overexpression of cytosolic OASS resulted in a 58-74% increase in protein-bound cysteine levels compared with non-transformed wild-type soybean seeds. A 22-32% increase in the free cysteine levels was also observed in transgenic soybeans overexpressing OASS. Furthermore, these transgenic soybean plants showed a marked increase in the accumulation of Bowman-Birk protease inhibitor, a cysteine-rich protein. The overall increase in soybean total cysteine content (both free and protein-bound) satisfies the recommended levels required for the optimal growth of monogastric animals.

Original languageEnglish (US)
Pages (from-to)13-23
Number of pages11
JournalPlanta
Volume235
Issue number1
DOIs
StatePublished - Jan 1 2012

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Cysteine Synthase
Genetically Modified Plants
proteinase inhibitors
Protease Inhibitors
Soybeans
Cysteine
cysteine
Seeds
genetically modified organisms
soybeans
seeds
Sulfur Amino Acids
sulfur
Proteins
seed development
cysteine synthase
Cysteine Proteinase Inhibitors
cysteine proteinase inhibitors
Soybean Proteins
monogastric livestock

Keywords

  • Bowman-Birk protease inhibitor
  • Cysteine
  • Essential amino acid
  • Nutritional quality
  • O-acetylserine sulfhydrylase
  • Soybean

ASJC Scopus subject areas

  • Genetics
  • Plant Science

Cite this

Transgenic soybean plants overexpressing O-acetylserine sulfhydrylase accumulate enhanced levels of cysteine and Bowman-Birk protease inhibitor in seeds. / Kim, Won Seok; Chronis, Demosthenis; Juergens, Matthew; Schroeder, Amy C.; Hyun, Seung Won; Jez, Joseph M.; Krishnan, Hari B.

In: Planta, Vol. 235, No. 1, 01.01.2012, p. 13-23.

Research output: Contribution to journalArticle

Kim, Won Seok ; Chronis, Demosthenis ; Juergens, Matthew ; Schroeder, Amy C. ; Hyun, Seung Won ; Jez, Joseph M. ; Krishnan, Hari B. / Transgenic soybean plants overexpressing O-acetylserine sulfhydrylase accumulate enhanced levels of cysteine and Bowman-Birk protease inhibitor in seeds. In: Planta. 2012 ; Vol. 235, No. 1. pp. 13-23.
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