Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm

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  • Jesper Harholt, Danmark
  • Inga C Bach, Danmark
  • Solveig Lind-Bouquin, Danmark
  • Kylie J Nunan, Department of Plant Biology and Biotechnology, Laboratory for Molecular Plant Biology, VKR Research Centre Pro-Active Plants, Faculty of Life Sciences, University of Copenhagen, Danmark
  • Susan M Madrid, Genencor-A Danisco Division, USA
  • Henrik Brinch-Pedersen
  • Preben B Holm, Danmark
  • Henrik V Scheller, Danmark
  • Molekylær Genetik og Bioteknologi
  • Institut for Genetik og Bioteknologi
Endo-xylanase (from Bacillus subtilis) or ferulic acid esterase (from Aspergillus niger) were expressed in wheat under the control of the endosperm-specific 1DX5 glutenin promoter. Constructs both with and without the endoplasmic reticulum retention signal (Lys-Asp-Glu-Leu) KDEL were used. Transgenic plants were recovered in all four cases but no qualitative differences could be observed whether KDEL was added or not. Endo-xylanase activity in transgenic grains was increased between two and threefold relative to wild type. The grains were shrivelled and had a 25%-33% decrease in mass. Extensive analysis of the cell walls showed a 10%-15% increase in arabinose to xylose ratio, a 50% increase in the proportion of water-extractable arabinoxylan, and a shift in the MW of the water-extractable arabinoxylan from being mainly larger than 85 kD to being between 2 and 85 kD. Ferulic acid esterase-expressing grains were also shrivelled, and the seed weight was decreased by 20%-50%. No ferulic acid esterase activity could be detected in wild-type grains whereas ferulic acid esterase activity was detected in transgenic lines. The grain cell walls had 15%-40% increase in water-unextractable arabinoxylan and a decrease in monomeric ferulic acid between 13% and 34%. In all the plants, the observed changes are consistent with a plant response that serves to minimize the effect of the heterologously expressed enzymes by increasing arabinoxylan biosynthesis and cross-linking.
OriginalsprogEngelsk
TidsskriftPlant Biotechnology Journal
Vol/bind8
Nummer3
Sider (fra-til)351-362
Antal sider12
ISSN1467-7644
DOI
StatusUdgivet - 2010

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