Changes in the Structure of Xyloglucan of Apple Fruit during Development

• Published in: Engei Gakkai zasshi Vol. 73; no. 1; pp. 51 - 56
• Main Authors: Ito, Seiko, Mitsuishi, Yasushi, Okuno, Toshikatsu, Kato, Yoji
• Format: Journal Article
• Language: English
• Published: THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 01.01.2004
• Subjects: apple; Starking Delicious; structural modification of xyloglucan
• ISSN: 0013-7626; 1880-358X
• DOI: 10.2503/jjshs.73.51

Cell-wall materials (80% methanol-insoluble fraction) of 'Starking Delicious' apple fruit obtained at different developmental stages were separated into water-soluble and water-insoluble polysaccharide fractions. Crude xyloglucans, prepared from both polysaccharide fractions, were hydrolyzed with Geotrichm sp. M128 xyloglucanase. The xyloglucanase- hydrolyzates were subjected to high-performance anion-exchange chromatography with pulsed amperometric detection before and after digestion with Eupenicillium sp. M9 isoprimeverose-producing oligoxyloglucan hydrolase. Both xyloglucan preparations were composed mainly of XXG, XXXG, XXLG, XLXG, XXFG, XLLG and XLFG [where each (1→4)-β-linked D-glucosyl residue in the backbone is given a one-letter code according to its substituents: G=β-D-Glc; X=α-D-Xyl-(1→6)-β-D-Glc; L=β-D-Gal-(1→2)-α-D-Xyl-(1→6)-β-D-Glc; F=α-L-Fuc-(1→2)-β-D-Gal-(1→2)-α-D-Xyl-(1→6)-β-D-Glc]. The ratios of fucose-containing oligosaccharide units (XXFG and XLFG) to fucose-noncontaining oligosaccharide units (XXG, XXXG, XXLG, XLXG and XLLG) in the water-insoluble xyloglucan molecules decreased with fruit development. The molar ratio of a pentasaccharide, XXG, in the water-soluble and -insoluble xyloglucan molecules increased with fruit development.