XYLOGLUCAN OCTASACCHARIDE XXLGOL DERIVED FROM THE SEEDS OF HYMENAEA COURBARIL ACTS AS A SIGNALING MOLECULE

Treatment of the xyloglucan isolated from the seeds of Hymenaea courba ril with Humicola insolens endo-1,4-beta-D-glucanase I produced xylogl ucan oligosaccharides, which were then isolated and characterized. The two most abundant compounds were the heptasaccharide (XXXG) and the o ctasaccharide (XXLG), which were examined by reference to the biologic al activity of other structurally related xyloglucan compounds. The re duced oligomer (XXLGol) was shown to promote growth of wheat (Triticum aestivum) coleoptiles independently of the presence of 2,4-dichloroph enoxyacetic acid (2,4-D). In the presence of 2,4-D, XXLGol at nanomola r concentrations increased the auxin-induced response. It was found th at XXLGol is a signaling molecule, since it has the ability to induce, at nanomolar concentrations, a rapid increase in an Lu-L-fucosidase r esponse in suspended cells or protoplasts of Robes fruticosus L. and t o modulate 2,4-D or gibberellic acid-induced alpha-L-fucosidase.