Expression patterns of cell wall-modifying enzymes during grape berry development

• Published in: Planta 2001-12, Vol.214 (2), p.257-264
• Main Authors: Nunan, Kylie J., Davies, Christopher, Robinson, Simon P., Fincher, Geoffrey B.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Berries; Biological and medical sciences; Blotting, Northern; Blotting, Southern; Cell Wall - genetics; Cell Wall - metabolism; Cell walls; Complementary DNA; Economic plant physiology; Enzymes; Enzymes - genetics; Enzymes - isolation & purification; Enzymes - metabolism; Fructification and ripening; Fructification, ripening. Postharvest physiology; Fruit - enzymology; Fruit - genetics; Fruit - growth & development; Fruits; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Growth and development; Messenger RNA; Plant physiology and development; Plants; Polysaccharides; Polysaccharides - metabolism; Ripening; RNA; RNA, Messenger - analysis; Transcription, Genetic; Vegetative and sexual reproduction, floral biology, fructification; Vitis - enzymology; Vitis - genetics; Vitis - growth & development
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250100609

During ripening of grape (Vitis vinifera L.) berries, softening occurs concomitantly with the second growth phase of the fruit and involves significant changes in the properties of cell wall polysaccharides. Here, the activities of enzymes that might participate in cell wall modification have been monitored throughout berry development. α-Galactosidase (EC 3.2.1.22), β-galactosidase (EC 3.2.1.23) and pectin methylesterase (EC 3.1.1.11) activities were present, but no polygalacturonase (EC 3.2.1.15), cellulase (EC 3.2.1.4), xyloglucanase (xyloglucan-specific cellulase EC 3.2.1.4) or galactanase (EC 3.2.1.89) could be detected. The accumulation of mRNAs encoding wall-modifying enzymes was examined by northern hybridization analysis. Transcripts for β-galactosidase, pectin methylesterase, polygalacturonase, pectate lyase (EC 4.2.2.2) and xyloglucan endotransglycosylase (EC 2.4.1.207) were present during ripening, although polygalacturonase activity had not been detected in berry extracts. Cellulases could not be detected in ripening berries, either at the enzyme or mRNA levels. The increase in β-galactosidase activity and mRNA is consistent with the observed decrease in type-I arabinogalactan content of the walls during ripening, and the detection of polygalacturonase and pectate lyase mRNAs might explain the increased solubility of galacturonan in walls of ripening grapes. Thus, the modification of cell wall polysaccharides during softening of grape berries is a complex process involving subtle changes to different components of the wall, and in many cases only small amounts of enzyme activity are required to effect these changes.