5 Control of Gene Expression in Phytopathogenic Ascomycetes During Early Invasion of Plant Tissue

Plant pathogenic fungi in the Ascomycota phylum are amongst some of the most destructive agents of plant disease. They use a variety of strategies to gain entry into the plant tissue with some biotrophs causing little damage early on, whilst other necrotrophs cause plant cell death very early in the interaction. Regardless of the strategy, the early stages of the interaction between these fungi and their plant hosts set the stage for either disease or non-disease outcome. The fungal molecules involved in this process are being identified functionally and through transcriptomic approaches in which uncharacterized secreted proteins are often highly upregulated. This chapter reviews the current state of our understanding about the molecules involved in the early stages of plant infection.