An extracellular transglutaminase is required for apple pollen tube growth

Research output: Contribution to journalArticle

View graph of relations Save citation


  • Alessia Di Sandro
  • Stefano Del Duca
  • Elisabetta Verderio
  • Alan J. Hargreaves
  • Alessandra Scarpellini
  • Giampiero Cai
  • Mauro Cresti
  • Claudia Faleri
  • Rosa A. Iorio
  • Shigehisa Hirose
  • Yutaka Furutani
  • Ian G.C. Coutts
  • Martin Griffin
  • Philip L.R. Bonner
  • Donatella Serafini-Fracassini

Research units


An extracellular form of the calcium-dependent protein-cross-linking enzyme TGase (transglutaminase) was demonstrated to be involved in the apical growth of Malus domestica pollen tube. Apple pollen TGase and its substrates were co-localized within aggregates on the pollen tube surface, as determined by indirect immunofluorescence staining and the in situ cross-linking of fluorescently labelled substrates. TGase-specific inhibitors and an anti-TGase monoclonal antibody blocked pollen tube growth, whereas incorporation of a recombinant fluorescent mammalian TGase substrate (histidine-tagged green fluorescent protein: His6-Xpr-GFP) into the growing tube wall enhanced tube length and germination, consistent with a role of TGase as a modulator of cell wall building and strengthening. The secreted pollen TGase catalysed the cross-linking of both PAs (polyamines) into proteins (released by the pollen tube) and His6-Xpr-GFP into endogenous or exogenously added substrates. A similar distribution of TGase activity was observed in planta on pollen tubes germinating inside the style, consistent with a possible additional role for TGase in the interaction between the pollen tube and the style during fertilization.

Request a copy

Request a copy


Original languageEnglish
Pages (from-to)261-271
Number of pages11
JournalBiochemical Journal
Issue number2
Publication statusPublished - 5 May 2010


  • extracellular space, germination, green fluorescent proteins, immunohistochemistry, malus, biological models, genetically modified plants, pollen tube, recombinant proteins, substrate specificity, transglutaminases


Employable Graduates; Exploitable Research

Copy the text from this field...