Apple (Malus domestica) and tomato (Lycopersicum esculentum) fruits cell-wall hemicelluloses and xyloglucan degradation during Penicillium expansum infection.

Abstract

We characterized the changes in cell-wall hemicellulosic polysaccharides and the hemicellulose-degrading enzymes associated with apple and tomato fruits infected by Penicillium expansum. Our results showed a reduction in the molecular mass of hemicelluloses, with this reduction being particularly notable in the xyloglucan associated with P. expansum infection. The activation of fungal beta-glucanases was also highlighted. Fruit xyloglucan endotransglucosylase/hydrolase (XTH)-specific activity decreased drastically during the infection process in both apple and tomato fruits. We suggest that XTH reduction during the infection might be related with the fungus attack mechanism. We also suggest that the decrease in activity and the consequent lower xyloglucan endotransglucosylation, together with the increase in endoglucanases, would permit fungal access to the cellulose-xyloglucan network, increase the efficiency of cellulose hydrolysis, and thus facilitate the progress of the fungal infection. The results confirm the importance of hemicellulose degradation in the breakdown of plant cell walls, causing cell-wall loosening, increasing the porosity of the wall, and allowing the colonization of plant tissue.

• Authors: Eva Miedes, Ester P Lorences
• Journal: Journal of agricultural and food chemistry (J Agric Food Chem) Vol. 52 Issue 26 Pg. 7957-63 (Dec 29 2004) ISSN: 0021-8561 [Print] United States
• PMID: 15612782 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Glucans
• Polysaccharides
• Xylans
• xyloglucan
• hemicellulose

Topics

• Cell Wall (chemistry)
• Fruit (chemistry, microbiology, ultrastructure)
• Glucans (metabolism)
• Solanum lycopersicum (ultrastructure)
• Malus (ultrastructure)
• Penicillium (enzymology)
• Plant Diseases (microbiology)
• Polysaccharides (metabolism)
• Xylans (metabolism)