Research Article

In vitro degradation of forage chicory (Cichorium intybus L.) by endopoly- galacturonase

  1. Xuezhao Sun1,3,*,
  2. Simone O Hoskin1,
  3. Ian G Andrew2,
  4. Keith N Joblin3,
  5. Philip J Harris4

Article first published online: 11 SEP 2007

DOI: 10.1002/jsfa.3045

Issue

Journal of the Science of Food and Agriculture

Journal of the Science of Food and Agriculture

Volume 87, Issue 15, pages 2860–2867, December 2007

Additional Information

How to Cite

Sun, X., Hoskin, S. O., Andrew, I. G., Joblin, K. N. and Harris, P. J. (2007), In vitro degradation of forage chicory (Cichorium intybus L.) by endopoly- galacturonase. J. Sci. Food Agric., 87: 2860–2867. doi: 10.1002/jsfa.3045

Author Information

  1. 1

    Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand

  2. 2

    Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand

  3. 3

    Grasslands Research Centre, AgResearch, Palmerston North, New Zealand

  4. 4

    School of Biological Sciences, The University of Auckland, Auckland, New Zealand

*Rumen, Nutrition and Welfare Section, Grasslands Research Centre, AgResearch Limited, Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand

Publication History

  1. Issue published online: 9 NOV 2007
  2. Article first published online: 11 SEP 2007
  3. Manuscript Accepted: 18 JUN 2007
  4. Manuscript Revised: 17 MAY 2007
  5. Manuscript Received: 6 MAR 2007

Funded by

  • Foundation for Research, Science and Technology.

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Keywords:

  • particle breakdown;
  • pectins;
  • plant cell walls;
  • chicory;
  • Cichorium intybus;
  • endopolygalacturonase (endo-PG);
  • pectinase

Abstract

BACKGROUND: Leaves of forage chicory break down rapidly in the rumen despite little or no rumination. Because chicory cell walls contain high concentrations of pectin, degradation of leaf midrib and leaf lamina tissues by pectinolytic enzymes was investigated.

RESULTS: Treatment with endopolygalacturonase (endo-PG) degraded fresh intact chicory leaves to particles of less than 1 mm in length and solubilised more than 70% of the dry matter within 16 h. Uronic acids were released more extensively than neutral monosaccharides. In similar treatments, 77% of white clover leaflets and 12% of perennial ryegrass leaf blades were solubilised or broken down to particles with a size of less than 1 mm. The degradation of pectic polysaccharides in chicory midribs was monitored by immunofluorescence labelling with monoclonal antibodies JIM5 and JIM7 which target partially methyl-esterified epitopes of the homogalacturonan (HG) domain of pectin. Examination by fluorescence microscopy revealed that cell separation in the cortical parenchyma of chicory midrib following endo-PG treatment was associated with loss of HG from the middle lamella, the corners of intercellular spaces and from the tricellular junctions.

CONCLUSION: The results of the current study suggest that one of the main contributions to chicory breakdown in the rumen may be cell separation caused by degradation of HG by pectinolytic enzymes from rumen bacteria. Copyright © 2007 Society of Chemical Industry

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