FUCOSYLATED XYLOGLUCAN IN SUSPENSION-CULTURED CELLS OF THE GRAMINEOUSMONOCOTYLEDON, FESTUCA-ARUNDINACEA

This work re-examines the idea that xyloglucans of the primary cell wa lls of graminaceous monocotyledons differ from those of most other hig her plants in lacking alpha-L-fucose residues. Suspension-cultured cel ls of Festuca arundinacea Schreber (tall fescue grass) incorporated ex ogenous L-[1-H-3]fucose into cell wall material. About 67% of the phen ol-insoluble H-3 could be extracted from these cell walls with 3.6 M K OH. About 40% of the KOH-extracted H-3 was converted into products of apparent molecular weight similar to 200-2000 by Trichoderma cellulase , and a discrete peak of this material eluted from Bio-Gel P-2 at K-av 0.40 suggesting a nonasaccharide. On paper chromatography in two solv ent systems, and HPLC on amino-silica, about 33% of the 3H in this fra ction co-migrated with an authentic nonasaccharide, Glc(4)Xyl(3)GalFuc (XXFG), which is generated from dicotyledonous xyloglucan by cellulas e digestion. In addition, the [H-3]nonasaccharide from Festuca and aut hentic XXFG yielded identical products when subjected to limited diges tion with the fungal glycanase mixture, Driselase. Taken together, the evidence indicates for the first time that grass cell walls contained a small amount of fucosylated xyloglucan.