The plant cell wall as a site for molecular contacts in fungal pathogenesis

• Mycosphaerella supprescins: host-specific determinants for plant disease.
• The supprescins condition susceptibility by manipulating the physiology of host cells.
• The supprescins interferes with elicitor-stimulated defense before the actual penetration.
• M. pinodes utilizes the host's jasmonic acid (JA)-mediated signaling pathway by targeting ecto-ATPase(s).

The plant cell wall, the most external layer of the plant surface, is the site where most pathogenic fungi first make contact with host cells. A plant–fungus interaction therefore commences at the interface between the plant and the spore. Our current research focusing on the plant cell wall has discovered an extracellular ecto-nucleoside triphosphate diphosphohydrolase (ecto-NTPDase/apyrase; EC3.6.1.15) as a key player in plant defense before the onset of PTI (PAMP-triggered immunity). This review focuses on our recent findings, especially the role of the plant cell wall in the extracellular defense against fungi as well as fungal strategies resulting in successful infection.