Tissue staining to study the fruiting process of Coprinopsis cinerea

Abstract

The coprophilous Coprinopsis cinerea is an edible model mushroom that grows and fruits very fast under laboratory conditions. Fruiting starts with primary hyphal knot (Pk) formation in the dark, followed by light-induced compact aggregates known as the secondary hyphal knots (Sks) in which stipe and cap tissues differentiate. Under defined fruiting conditions, primordium development (P1 to P5) takes five days to culminate on Day 6 of development in karyogamy (K) and meiosis (M) within the basidia and subsequent basidiospore production which parallels fruiting body maturation (stipe elongation and cap expansion). Mature fruiting bodies autolyze on Day 7 to release the spores in liquid droplets to the ground. By applying different histochemical staining techniques for the light microscopy, primordial sections of C. cinerea were examined to study different tissues and cell types which appear over the time in the fruiting process. Lactophenol blue, Mayer’s hemalum, malachite green and eosin all stained probasidia stronger than other tissues. The pileipellis was best stained by malachite green and lactophenol blue. Periodic acid Schiff (PAS) stained the pileipellis better dark and the subhymenium slightly darker as compared to other tissues. All stains were also applied in combinations of two, in both possible orders. In double staining with PAS and hemalum, the subhymenium and probasidia were best differentiated.