Expression of UDP-glucose dehydrogenase reduces cell-wall polysaccharide concentration and increases xylose content in alfalfa stems

Deborah A. Samac, Lynn Litterer, Glena Temple, Hans Joachim G. Jung, David A. Somers

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The primary cell-wall matrix of most higher plants is composed of large amounts of uronic acids, primarily D-galacturonic acid residues in the backbone of pectic polysaccharides. Uridine diphosphate (UDP)-glucose dehydrogenase is a key enzyme in the biosynthesis of uronic acids. We produced transgenic alfalfa (Medicago sativa) plants expressing a soybean UDP-glucose dehydrogenase cDNA under the control of two promoters active in alfalfa vascular tissues. In initial greenhouse experiments, enzyme activity in transgenic lines was up to seven-fold greater than in nontransformed control plants; however, field-grown transgenic plants had only a maximum of 1.9-fold more activity than the control. Cell-wall polysaccharide content was lower and Klason lignin content was higher in transgenics compared to the nontransformed control. No significant increase in pectin or uronic acids in the polysaccharide fraction was observed in any line. Xylose increased 15% in most transgenic lines and mannose concentration decreased slightly in all lines. Because of the complexity of pectic polysaccharides and sugar biosynthesis, it may be necessary to manipulate multiple steps in carbohydrate metabolism to alter the pectin content of alfalfa.

Original languageEnglish (US)
Pages (from-to)1167-1182
Number of pages16
JournalApplied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology
Volume116
Issue number1-3
DOIs
StatePublished - Mar 1 2004

Keywords

  • Carbohydrate
  • Forage
  • Homogalacturonan
  • Lucerne
  • Protein utilization

Fingerprint Dive into the research topics of 'Expression of UDP-glucose dehydrogenase reduces cell-wall polysaccharide concentration and increases xylose content in alfalfa stems'. Together they form a unique fingerprint.

Cite this