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Non-cellulosic polysaccharide distribution during G-layer formation in poplar tension wood fibers: abundance of rhamnogalacturonan I and arabinogalactan proteins but no evidence of xyloglucan

Planta volume 246, pages 857–878 (2017)Cite this article

Abstract

Main conclusion

RG-I and AGP, but not XG, are associated to the building of the peculiar mechanical properties of tension wood.

Hardwood trees produce tension wood (TW) with specific mechanical properties to cope with environmental cues. Poplar TW fibers have an additional cell wall layer, the G-layer responsible for TW mechanical properties. We investigated, in two poplar hybrid species, the molecules potentially involved in the building of TW mechanical properties. First, we evaluated the distribution of the different classes of non-cellulosic polysaccharides during xylem fiber differentiation, using immunolocalization. In parallel, G-layers were isolated and their polysaccharide composition determined. These complementary approaches provided information on the occurrence of non-cellulosic polysaccharides during G-fiber differentiation. We found no evidence of the presence of xyloglucan (XG) in poplar G-layers, whereas arabinogalactan proteins (AGP) and rhamnogalacturonan type I pectins (RG-I) were abundant, with an apparent progressive loss of RG-I side chains during G-layer maturation. Similarly, the intensity of immunolabeling signals specific for glucomannans and glucuronoxylans varies during G-layer maturation. RG-I and AGP are best candidate matrix components to be responsible for TW mechanical properties.

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Abbreviations

AGP:

Arabinogalactan protein

HG:

Homogalacturonan

HPAEC-PAD:

High-performance anion exchange chromatography with pulsed amperometric detection

MALDI-TOF MS:

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry

ML:

Middle lamella

OW:

Opposite wood

PCW:

Primary cell wall

RG-I (II):

Rhamnogalacturonan type I (type II) pectin

TW:

Tension wood

XG:

Xyloglucan

XGO:

Xyloglucan oligomers

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Acknowledgements

This work was partly supported by the “Stress in Trees” Project ANR-12-BS09-0004. FTP Guedes was funded by CAPES (Ministry of Education, Brazil). We would like to thank Pierre-Ivan Raynal (Electron Microscopy Facility, François Rabelais University and University Hospital of Tours, France) for technical support for MET observations. Confocal microscopy was carried out in Xylobiotech Facility funded by the IA project “Xyloforest” (ANR-10-EQPX-16).

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  1. Fernanda Trilstz Perassolo Guedes

    Present address: Faber-Castell, São Carlos, Brazil

  2. Carole Assor

    Present address: IATE, INRA, 34060, Montpellier, France

Affiliations

  1. AGPF, INRA, 45075, Orléans, France

    Fernanda Trilstz Perassolo Guedes, Françoise Laurans, Véronique Lainé-Prade, Nathalie Boizot, Marie-Claude Lesage-Descauses, Jean-Charles Leplé, Annabelle Déjardin & Gilles Pilate

  2. BIA, INRA, 44316, Nantes, France

    Bernard Quemener, Carole Assor & Jacqueline Vigouroux

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  1. Fernanda Trilstz Perassolo Guedes
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Guedes, F.T.P., Laurans, F., Quemener, B. et al. Non-cellulosic polysaccharide distribution during G-layer formation in poplar tension wood fibers: abundance of rhamnogalacturonan I and arabinogalactan proteins but no evidence of xyloglucan. Planta 246, 857–878 (2017). https://doi.org/10.1007/s00425-017-2737-1

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Keywords

  • Cellulose aggregation
  • G-fiber maturation
  • Hemicellulose
  • Hydrogel formation
  • Mechanical strain
  • Pectin