Xylan, comprising a xylose backbone with substituted sugar units, is the most abundant hemicellulose of secondary cell walls of higher plants, where its interactions with lignin and cellulose confer structural rigidity to the cell wall. Understanding the lignin-xylan interactions may enable development of plants with novel cell wall characteristics, potentially beneficial for production of pulp and chemicals. In this work, fungal xylan-degrading enzymes, including FC1, DFC2 and DFC4 were targeted for introduction into Arabidopsis thaliana and aspen under control of the wood specific promoter to investigate their effect on xylan structure and lignin-xylan interactions. Furthermore, a signal peptide of a secreted cellulase was fused to enzymes sequences in FC1 at N-terminus for targeting of recombinant enzymes to the cell wall whereas other constructs used native fungal SP. GUS reporter staining assay of hybrid aspen showed that the promoter used exhibits wood specific expression. Confocal microscopy analysis of A. thaliana lines transformed with of GFP-fused fungal constructs FC1 and DFC4 with targeted signal peptides showed targeted enzymes localized to the cell wall. Vectors for wood-specific expression in planta were cloned with FC1 and DFC4.