Gene networks orchestrate dynamic gene expression patterns that coordinate developmental and physiological processes. Genetic drift, due to mutation, can lead to networks loosing or gaining targets over time. When enough targets have changed, new phenotypes can arise from the divergent networks. This phenomenon, transcriptional rewiring, is the result of cumulative mutations in regulators and/or target sequences, and is a growing area of interest in evolutionary biology. We aim to investigate transcriptional rewiring at the inter-species and intra-species levels for species which have developed extreme states of an ancestral phenotype. We have chosen to investigate rewiring of the plant cell wall deconstruction network because of rising interest in renewable biofuels and products from biomass, and its importance in fungal pathology.