Secretion of cell wall degrading enzymes is a major factor in the penetration and colonization of host plants by bacterial, fungal and Oomycete pathogens. Plant pathogen genomes often contain hundreds of genes encoding plant cell wall degrading enzymes, most likely in order to facilitate the degradation of the highly diverse polysaccharides found in plant cell walls. Patterns of expression of pathogen cell wall degrading enzymes are complex and our understanding of the regulation of enzyme synthesis is still very limited. We are currently investigating patterns of expression of pathogen cell wall degrading enzyme genes in vitro and during infection using RNA-Seq next-generation sequencing and quantitative real-time PCR. The aim of our research is to elucidate patterns of enzyme production and the role of the enzymes in pathogen virulence.