Study of Hypsizygus marmoreus (Peck) Bigel. and Grifola frondosa (Dicks.: Fr.) S.F. Gray: Cultural-morphological peculiarities, growth characteristics, qualitative enzymatic activity, and resistance to fungal pest contamination

Hypsizygus marmoreus (HM) and Grifola frondosa (GF) are two highly praised culinary-medicinal mushrooms with good taste, texture, and fragrance. They possess health-enhancing properties and good commercial potential worldwide. We aimed to develop biotechnologically viable cultivation methods for these mushrooms, and to reveal the taxonomic significance of several growth and macro- and micromorphological characteristics of vegetative mycelia. Among the HM strains, we have documented vegetative mycelium with incrustations, networks of vegetative hyphae, some with short side protuberances, arthroconidia, some of them connected as chains, chlamydospores and intercalary chlamydospores, and clamp connections. GF structures included vegetative hyphae with clamps, anastomoses, and terminal chlamydospores. We have found that HM strains favored malt extract agar (MEA) and wort agar (WA) the most, with pH of 5.5 and 6.0. A growth coefficient of 47.3 was the highest and belonged to HM strain 571. Among GF strains, potato dextrose agar (PDA) was the most favored media at pH 4.5; GC of 58.2 was the highest and belonged to GF strain 924. In the solid-state measurement of laccase activity on guaiacol, we have found that enzyme secretion was associated with the agar media, or guaiacol, and not with the supplement, sawdust, or straw. Other enzymes demonstrated very low activity. When observing the relationship between the study mushroom mycelia and pest fungi, we have found that in all strains of the study mushrooms Aspergillus versicolor formed a border with GF and later overgrew it; HM formed a border with A. versicolor and later overgrew it; and Penicillium brevicompactum inhibited both HM and GF. Both mushrooms and pests did not form any contact with each other during these studies. The above-mentioned characteristics could be useful in culture for in vitro identification protocol of screened species during their biotechnological cultivation process.