Effects of Heat Stress and Exogenous Salicylic Acid on Secondary Metabolites Biosynthesis in Pleurotus ostreatus (Jacq.) P. Kumm.

Pleurotus ostreatus (Jacq.) P. Kumm has high medicinal value, but few studies exist on regulating secondary metabolite biosynthesis. Environmental factors play a substantial role in the accumulation of microbial secondary metabolites. In this study, the effects of heat stress (24 h) and salicylic acid (0.05 mmol/L) treatment on the secondary metabolism of P. ostreatus were analyzed by metabolome, transcriptome, and gene differential expression analysis. Metabolome and transcriptome analyses showed that salicylic acid significantly increased the accumulation of antibiotics and polyketones, while heat stress increased the accumulation of flavonoids, polyketones, terpenoids, and polysaccharides. The content and the biosynthetic genes expression of heparin were markedly increased by heat stress, and the former was increased by 4565.54-fold. This study provides a reference for future studies on secondary metabolite accumulation in edible fungi.

The quality of compost was improved by low concentrations of fulvic acid owing to its optimization of the exceptional microbial structure.

The influence of different concentrations of fulvic acid at 0, 100, 200, and 400 mg/kg was evaluated during the course of composting with straw and mushroom residues as substrates. The optimal concentration of fulvic acid is 100 mg/Kg based on microbial characteristics, chemical parameters, and germination index testing. Nearly 80% of the microbial taxa responded significantly to fulvic acid over the composting period, with a dynamic change of the co-occurrence network from complex to simple and then to complex. Fulvic acid accelerated the progress of composting and reduced the emission of gases at the thermophilic phase. The optimal concentration of fulvic acid enriched the beneficial microorganisms Aeribacillus, Oceanobacillus, and Rhodospirillaceae, and decreased the abundances of pathogenic microorganisms Corynebacterium, Elizabethkingia, and Sarcocystidae. This study indicates a new strategy to optimize the composting process using the biostimulant fulvic acid.

Four new sesquiterpenoids from cultures of the fungus Funalia trogii.

Four new drimane sesquiterpenoids, named as funatrols A-D, together with isodrimenediol, were isolated from cultures of the fungus Funalia trogii. The new structures were elucidated by means of spectroscopic methods. All compounds were tested for their cytotoxicities against five human cancer cell lines.

Activity of armillarisin B in vitro against plant pathogenic fungi.

The methanolic extract of the fruiting bodies of the mushroom Armillariella tabescens was found to show antifungal activity against Gibberella zeae. The active compound was isolated from the fruiting bodies of A. tabescens by bioassay-guided fractionation of the extract and identified as armillarisin B. Armillarisin B eventually corresponds to 2-hydroxy-2-phenylpropanediamide and its structure was confirmed on the basis of spectroscopic studies including 2D NMR experiments.