Thin PTFE-like membranes allow characterizing germination and mechanical penetration competence of pathogenic fungi

Investigating the penetration behavior of pathogenic fungi often fails because natural substrata vary significantly with respect to morphological and microstructural properties. To establish in vitro penetration assays, reproducible production of thin membranes with defined properties such as thickness, mechanical and chemical stability, roughness and hydrophobicity is essential. In this paper we describe the fabrication and characterization of membranes mimicking plant surfaces with respect to hydrophobicity and report on penetration assays with plant pathogenic fungi known to exert enormous force during the infection process. In order to reach high hydrophobicity, polytetrafluoroethylene-like membranes were used. By varying membrane thickness, the penetration competence of different pathogens could be evaluated and quantified. In addition, a relationship between surface roughness in the nanometer scale and the germination rate has been observed.