Visualization and partial characterization of the ECM of Pestalotia malicola on artificial and natural substrata

Abstract

The extracellular matrix (ECM) released by conidia of Pestalotia malicola when incubated on artificial and natural substrata was investigated. Scanning electron microscopy (SEM) images indicated the presence of ECM beneath conidial appendages. Stains for non-specific esterase activity revealed that enzyme activity was initially present at the conidial appendages. Gelatin peel tests observed with light microscopy and SEM indicated that a strong initial spore adhesion occurs at the appendages flanking the conidium body. That the ECM was seen beneath firmly adhered conidial appendages suggests that it has a role in adhesion. Harvested ECM material from germinating conidia was deglycosylated and acetylated for GC/MS monosaccharide identification. Mole percent calculations show mannose to be the predominant monosaccharide present.