Fungal Volatiles as Olfactory Cues for Female Fungus Gnat, Lycoriella ingenua in the Avoidance of Mycelia Colonized Compost.

The chemical signatures emitted by fungal substrates are key components for mycophagous insects in the search for food source or for suitable oviposition sites. These volatiles are usually emitted by the fruiting bodies and mycelia. The volatiles attract fungivorous insects, like flowers attract pollinators; certain flowers mimic the shape of mushroom fruiting bodies and even produce a typical mushroom odor to exploit on fungus-insect mutualism. There are numerous insects which are mycophagous or eat fungi additionally, but only a few are considered a threat in agriculture. Lycoriella ingenua is one of the most serious pests in mushroom cultivation worldwide. Here we attempt to examine the role of environmental volatiles upon behavioral oviposition preference. In two-choice bioassays, fungus gnats preferred uncolonized compost compared to colonized compost but preferred colonized compost against nothing. However, when colonized compost was paired against distilled water, no significant choice was observed. The comparison of fresh casing material and mycelium colonized casing material resulted in no significant preference. From colonized compost headspace, three antennally active volatiles were isolated by gas chromatography coupled with electroantennography and subsequently identified with gas chromatography coupled mass spectrometry as 1-hepten-3-ol, 3-octanone and 1-octen-3-ol. In behavioral assays the addition of said synthetic volatiles to uncolonized compost separately and in combination to mimic colonized compost resulted in avoidance. We thus partially elucidate the role of fungal volatiles in the habitat seeking behavior of Lycoriella ingenua.

Application of Near-Infrared Spectroscopy to Investigate Some Endogenic Properties of Pleurotus ostreatus Cultivars.

Fourteen different Pleurotus ostreatus cultivars (Po_1-Po_14) were tested for free amino acid content (fAA), total polyphenol content (TPC), and antioxidant capacity (Ferric Reducing Ability of Plasma-FRAP) to select the cultivars with the most favorable traits. Automatic amino acid analyzer (fAA) and spectrophotometric assay (TPC, FRAP) results as well as Fourier-transform near infrared (FT-NIR) spectra were evaluated with different chemometric methods (Kruskal-Wallis test, Principal Component Analysis-PCA, Linear Discriminant Analysis-LDA). Based on total free amino acid concentrations and FRAP values, the Po_2 cultivar was found to be the most favorable. Types Po_3, Po_8, Po_10 and Po_12 were separated using PCA. Based on the spectral profile, they may contain polyphenols and reducing compounds of different qualities. LDA classification that was based on the concentrations of all free amino acids, cysteine, and proline of the cultivars was performed with an accuracy of over 90%. LDA classification that was based on the TPC and FRAP values was performed with an accuracy of over 83%.

Accumulation of HT-2 toxin from contaminated mushroom compost by edible Agaricus bisporus.

Wheat straw is commonly used as a cellulose source in mushroom compost and could be a secondary source of mycotoxin contamination in the food chain. We cultivated edible Agaricus bisporus and Pleurotus ostreatus on T-2/HT-2 artificially-contaminated mushroom compost and developed and in-house validated an UHPLC-MS/MS method for determination of T-2, HT-2, T2-triol and T2-tetraol in mushroom compost and mushroom basidiocarp. A rapid phase I metabolization of T-2 and HT-2 in mushroom compost was observed. In Agaricus bisporus, basidiocarps 8-15 µg kg-1 accumulation of HT-2 calculated on wet weight was measured. No detectable mycotoxins were found in Pleurotus ostreatus basidiocarp.

Gene age shapes the transcriptional landscape of sexual morphogenesis in mushroom-forming fungi (Agaricomycetes).

Multicellularity has been one of the most important innovations in the history of life. The role of gene regulatory changes in driving transitions to multicellularity is being increasingly recognized; however, factors influencing gene expression patterns are poorly known in many clades. Here, we compared the developmental transcriptomes of complex multicellular fruiting bodies of eight Agaricomycetes and Cryptococcus neoformans, a closely related human pathogen with a simple morphology. In-depth analysis in Pleurotus ostreatus revealed that allele-specific expression, natural antisense transcripts, and developmental gene expression, but not RNA editing or a 'developmental hourglass,' act in concert to shape its transcriptome during fruiting body development. We found that transcriptional patterns of genes strongly depend on their evolutionary ages. Young genes showed more developmental and allele-specific expression variation, possibly because of weaker evolutionary constraint, suggestive of nonadaptive expression variance in fruiting bodies. These results prompted us to define a set of conserved genes specifically regulated only during complex morphogenesis by excluding young genes and accounting for deeply conserved ones shared with species showing simple sexual development. Analysis of the resulting gene set revealed evolutionary and functional associations with complex multicellularity, which allowed us to speculate they are involved in complex multicellular morphogenesis of mushroom fruiting bodies.

In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae).

Certain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105-109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

Volatile Composition of Some Cultivated and Wild Culinary-Medicinal Mushrooms from Hungary.

The volatile constituents of the fruiting bodies of 4 culinary-medicinal mushroom species (Agaricus bisporus, Boletus edulis, Cantharellus cibarius, and Hericium erinaceus) from Hungary were examined to review their aroma composition. Simultaneous distillation/extraction was applied to extract volatile compounds from fungi, and the values were measured with gas chromatography--mass spectrometry. Although the fragrances of fungi are not as characteristic as those of spices, several groups of volatile compounds have been found in mushrooms. The number of identified components ranged between 61 and 100, with a high ratio of 8-carbon volatiles generally occurring in fungi. Beyond common properties, individual attributes have been identified as well: an outstanding ratio of benzene compounds in champignons, numerous N-containing volatiles in boletes, carotenoid degradation products in chanterelles, and esters and fatty acids with a high carbon number in the lion's mane mushroom. The identification of these characteristic fragrance constituents can be very important in differentiating between species and confirming their presence in mushroom products.

Gas chromatography-mass spectrometry confirmation of the sensory scent features of the most commonly consumed Agaricus bisporus and Agaricus subrufescens exhibiting anticancerous traits.

In Hungary, fairly little is known about Agaricus subrufescens Peck (formerly called Agaricus blazei Murrill), which is cultivated on an industrial scale in the Far East. Nevertheless, this mushroom species exerts a curative influence and might become a new pillar of cancer research and antitumorous therapy. The present study gives a detailed discussion on the compositional differences of the scent components of A. subrufescens and its close relative Agaricus bisporus based on gas chromatography-mass spectrometry measurements, subsequent to Likens-Nickerson simultaneous distillation-extraction.

Mineral composition of different strains of edible medicinal mushroom Agaricus subrufescens Peck.

Agaricus subrufescens Peck is a well-known Basidiomycota fungus (Royal Sun Agaricus), with rising demand in consumption and production worldwide. This particular mushroom with high medical value has been used successfully in cancer therapy and in the treatment of some bacterial and viral diseases. Four strains of A. subrufescens (Si2.2, 853, 1105, and 2603) were cultivated, and 22 mineral elements of basidiomes (fruit bodies) were analyzed (caps and stipes separately). The data obtained about the mineral compositions were compared to the "reference" Agaricus bisporus (white button mushroom) and to the average of wild growing Agaricus species. The mineral composition of A. subrufescens strains can be characterized by the following: (1) high levels of valuable macroelements, i.e., potassium (28-30,000 mg/kg of dry matter), phosphorus (7-11,000 mg/kg of dry matter), and calcium and magnesium (for both elements, 1,000-1,500 mg/kg of dry matter); (2) significantly higher level of copper (compared to A. bisporus, 70-150 mg/kg of dry matter) and zinc (140-250 mg/kg of dry matter); (3) low quantity of sodium (140-180 mg/kg of dry matter); (4) attention should paid to the detectable amount of cadmium (2-17 mg/kg of dry matter) in strain Si2.2; (5) low or undetectable concentrations of some other poisonous microelements like As, Cr, and V; and (6) the distribution of elements in caps and stipes is characteristic-the majority of beneficial elements have higher contents in caps than in stipes, but some other elements, such as Ca, Fe, and Na, appear in an inverse proportion. In conclusion, it can be said that the mineral composition of A. subrufescens is definitely positive, with the exception of the above-mentioned Cd level.