Planta

, Volume 195, Issue 3, pp 352–361

Cell-type specific, coordinate expression of two ADP-glucose pyrophosphorylase genes in relation to starch biosynthesis during seed development of Vicia faba L.

Authors

  • Hans Weber
    • Institut für Pflanzengenetik und Kulturpflanzenforschung
  • Ute Heim
    • Institut für Pflanzengenetik und Kulturpflanzenforschung
  • Ljudmilla Borisjuk
    • Institut für Pflanzengenetik und Kulturpflanzenforschung
  • Ulrich Wobus
    • Institut für Pflanzengenetik und Kulturpflanzenforschung
Article

DOI: 10.1007/BF00202592

Cite this article as:
Weber, H., Heim, U., Borisjuk, L. et al. Planta (1995) 195: 352. doi:10.1007/BF00202592

Abstract

Several cDNA clones encoding two different ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.27) polypeptides denoted VfAGPC and VfAGPP were isolated from a cotyledonary library of Vicia faba L. Both sequences are closely related to AGPase small-subunit sequences from other plants. Whereas mRNA levels of VfAGPP were equally high in developing cotyledons and leaves, the mRNA of VfAGPC was present in considerable amounts only in cotyledons. During development of cotyledons, both mRNAs accumulated until the beginning of the desiccation phase and disappeared afterwards. The increase of AGPase activity in cotyledons during the phase of storage-product synthesis was closely followed by the accumulation of starch. The AGPase activity in crude extracts of cotyledons was insensitive to 3-phosphoglycerate whereas the activity from leaves could be activated more than five-fold. Inorganic phosphate inhibited the enzyme from both tissues but was slightly more effective on the leaf enzyme. There was a correlation at the cellular level between the distribution of VfAGPP and VfAGPC mRNAs and the accumulation of starch, as studied by in-situ hybridisation and by histochemical staining in parallel tissue sections of developing seeds, respectively. During the early phase of seed development (12–15 days after fertilization) VfAGPase mRNA and accumulation of starch were detected transiently in the hypodermal, chlorenchymal and outer parenchymal cell layers of the seed coat but not in the embryo. At 25 days after fertilization both synthesis of VfAGPase mRNA and biosynthesis of starch had started in parenchyma cells of the inner adaxial zone of the cotyledons. During later stages, the expression of VfAGPase and synthesis of starch extended over most of the cotyledons but were absent from peripheral cells of the abaxial zone, provascular and procalyptral cells.

Key words

ADP-glucose pyrophosphorylase (cDNA-cloning, sequencing)Gene expression (ADP-glucose pyrophospharylase, seed development)Metabolic regulation (ADP-glucose pyrophospharylase)Seed developmentStarch biosynthesisVicia

Abbreviations

AGPase

ADP-glucose pyrophosphorylase

DAF

days after fertilization

Glc1P

glucose-1-phosphate

3-PGA

3-phosphoglycerate

VfAGPC

AGPase subunit of Vicia faba mainly expressed in cotyledons

VfAGPP

AGPase subunit of Vicia faba mainly expressed in leaves and cotyledons

pVfAGPC, pVfAGPP

plasmids containing VfAGPC and VfAGPP, respectively

Copyright information

© Springer-Verlag 1995