Methods for altering the N-glycosylation pattern of proteins in higher plantsare provided. The methods comprise introducing into the plant a recombinantconstruct that provides for the inhibition of expression of αl,3-fucosyltransferase(FucT) and β 1 ,2-xylosyltransferase (XyIT) in a plant. Use of these constructsto inhibit or suppress expression of both of these enzymes, and isoforms thereof,advantageously provides for the production of endogenous and heterologousproteins having a "humanized" N-glycosylation pattern withoutimpacting plant growth and development. Stably transformed higher plants havingthis protein N-glycosylation pattern are provided. Glycoprotein compositions,including monoclonal antibody compositions, having substantially homogeneousglycosylation profiles, and which are substantially homogeneous for the GOglycoform, are also provided.
