Characterization of plants expressing the human β1,4-galactosyltrasferase gene

Jeannine Schneider, Alexandra Castilho, Martin Pabst, Friedrich Altmann, Clemens Gruber, Richard Strasser, Pia Gattinger, Georg J. Seifert, Herta Steinkellner*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

26 Citations (Scopus)


Modification of the plant N-glycosylation pathway towards human type structures is an important strategy to implement plants as expression systems for therapeutic proteins. Nevertheless, relatively little is known about the overall impact of non-plant glycosylation enzymes in stable transformed plants. Here, we analyzed transgenic lines (Nicotiana benthamiana and Arabidopsis thaliana) that stably express a modified version of human β1,4-galactosyltransferase (STGalT). While some transgenic plants grew normally, other lines exhibited a severe phenotype associated with stunted growth and developmental retardation. The severity of the phenotype correlated with both increased STGalT mRNA and protein levels but no differences were observed between N-glycosylation profiles of plants with and without the phenotype. In contrast to non-transgenic plants, all STGalT expressing plants synthesized significant amounts of incompletely processed (largely depleted of core fucose) N-glycans with up to 40% terminally galactosylated structures. While transgenic plants showed no differences in nucleotide sugar composition and cell wall monosaccharide content, alterations in the reactivity of cell wall carbohydrate epitopes associated with arabinogalactan-proteins and pectic homogalacturonan were detected in STGalT expressing plants. Notably, plants with phenotypic alterations showed increased levels of hydrogen peroxide, most probably a consequence of hypersensitive reactions. Our data demonstrate that unfavorable phenotypical modifications may occur upon stable in planta expression of non-native glycosyltransferases. Such important issues need to be taken into consideration in respect to stable glycan engineering in plants.

Original languageEnglish
Pages (from-to)39-47
JournalPlant Physiology and Biochemistry
Publication statusPublished - 2015
Externally publishedYes


  • Developmental phenotype
  • Glyco-engineering
  • Nicotiana benthamiana
  • Transgenic plants
  • β1,4-Galactosylation


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