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Journal article

A new structural element containing glycine-rich proteins and rhamnogalacturonan I in the protoxylem of seed plants

  • Ryser, Ulrich Plant Biology, Department of Biology, University of Fribourg, Switzerland
  • Schorderet, Martine Plant Biology, Department of Biology, University of Fribourg, Switzerland
  • Guyot, Romain Institute of Plant Biology, University of Zürich, Switzerland
  • Keller, Beat Institute of Plant Biology, University of Zürich, Switzerland
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    2004
Published in:
  • Journal of Cell Science. - 2004, vol. 117, no. 7, p. 1179-1190
Extracellular matrix
Glycine-rich cell-wall protein
Plant anatomy
Protoxylem
Rhamnogalacturonan I
Seed plants (spermatophytes)
English The water pipes of elongating plant organs are the result of programmed cell death and are formed by the walls of dead and empty protoxylem elements. These protoxylem elements are passively elongated many times by the surrounding tissue before they are replaced and collapse. Well-known adaptations for this unique task include the characteristic secondary wall thickenings, forming rings and helices. A new, clearly distinct structural element containing glycine-rich proteins is now visualized for the first time, using confocal laser scanning microscopy in the mature protoxylem of elongating organs of seed plants. This structural element is arranged along the longitudinal axis of the protoxylem elements. It interconnects the secondary wall thickenings within and between protoxylem elements, as well as the protoxylem with other cell types such as xylem parenchyma cells and metaxylem elements. The structural element is stable against detergent extractions, proteinase, pectinase and cellulase hydrolysis, and is closely associated with rhamnogalacturonan-I, a pectic polysaccharide. The results clearly demonstrate that the cell wall of protoxylem cells is a highly dynamic and complex structure. The typical polysaccharide-rich primary wall of living and elongating plant cells is progressively modified and finally replaced by a protein-rich wall in the dead and passively stretched protoxylem elements. These glycine-rich walls originated early in the evolution of the seed plants as confirmed by the analysis of genomic information.
Faculty
Faculté des sciences et de médecine
Department
Département de Biologie
Language
  • English
Classification
Biological sciences
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/299624
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