Additionally, several gene deletion studies on especially S. light and low concentrations of CO 2 have been proven to be necessary for proper fruiting body development (Kinugawa et al. The fruiting process is regulated by environmental factors e.g. In mature fruiting bodies of Basidiomycota, karyogamy and meiosis take place in the basidium, leading to the formation of basidiospores that are released during sporulation and marking the beginning of a new life cycle (Oberwinkler 1982). Subsequently, differentiated primordia develop into fruiting bodies primarily due to cell elongation rather than cell differentiation (Kües 2000). Cell differentiation results in the formation of bipolar primordia already comprising the plectenchyme as characteristic tissue for mature fruiting bodies. The hyphal knots develop successively into fruiting body initials (secondary hyphal knots) (Kües 2000 Kües and Liu 2000 Kües et al. It starts with the aggregation of hyphae to form mycelial cords, developing on local spots of the mycelium into hyphal knots by intense branching. The formation of fruiting bodies is one of the most complex developmental processes in the fungal life cycle (Sánchez-García et al. aegerita showed that the vegetative mycelium rather than the fruiting body is the origin of the sesquiterpenes (Orban et al. Applying this system on Cyclocybe aegerita, remarkable relations between fruiting body development and VOC compositions, especially counting for the release of sesquiterpenes during sporulation, have been depicted (Orban et al. Recently, we established a system consisting of modified crystallizing dishes allowing a non-invasive analysis of fungal VOCs from complete cultures during different stages of the fungal life cycle using solid-phase microextraction coupled gas chromatography mass spectrometry (SPME–GC–MS) (Orban et al. Studies analysing fungal volatilomes under more natural circumstances are rare. Furthermore, the focus on fruiting bodies neglects the role of the mycelium for VOC formation and possible interactions between fruiting bodies and mycelium during development. Prior to extraction, fruiting bodies are often grinded or otherwise damaged, which can result in unnatural VOC compositions (Combet et al. 2008) analysing the aroma profiles in context of food quality. Studies investigating volatilomes during the fungal life cycle are mainly focusing on fruiting bodies of mushrooms (Cho et al. However, studies investigating volatilomes (the composition of all VOCs produced by a fungus during one time point) are often focusing on one developmental stage ignoring potential dynamics in VOC release. 2015 Dickschat 2017 Fraatz and Zorn 2011 Kleofas et al. VOC profiles of several fungi have been analysed so far (Chen and Ho 1986 Costa et al. the quality of edible fungal fruiting bodies. More than 300 distinct fungal volatile organic compounds (VOCs) have been identified so far, being in many cases aroma active (Dickschat 2017) that determine, e.g. Future studies are needed to reveal whether FRGs directly regulates VOC formation or indirectly by changing the phenotype. commune, especially counting for sesquiterpenes.

Our results show remarkable connections between FRGs, fruiting body development and VOC production in S. Several sesquiterpenes, including α-guaiene, chamigrene and γ-gurjunene, were only found in presence of fruiting bodies. However, the sesquiterpenes found in the HS of FRG-deletion strains, namely, ( E)-nerolidol, δ-cadinene, L-calamenene, α-bisabolol and β-bisabolene, were not present in hom2 con or wild-type strains that mainly formed fruiting bodies and barely mycelium. In contrast to fruiting body forming strains, Δ tea1Δ tea1, Δ wc-2Δ wc-2, Δ hom2Δ hom2 and Δ fst4Δ fst4 showed less sesquiterpenes in the HS. Compared to the wild type, in the HS of hom2 con samples, that are able to form fruiting bodies, methyl 2-methylbutanoate was the most abundant substance at early stages (68–81% of the total peak area). Early developmental stages of these strains were dominated by esters, including methyl 2-methylbutanoate, ethyl 2-methylbutanoate, isobutyl 2-methylpropionate, and 2-methylbutyl acetate, of which the last three were not found in the headspace (HS) of the wild-type samples. The deletion strains Δ tea1Δ tea1, Δ wc-2Δ wc-2 and Δ hom2Δ hom2 were unable to develop fruiting bodies, and Δ fst4Δ fst4 formed only rudimentary fruiting body structures. We analysed the volatilomes of Schizophyllum commune during different developmental stages in a variety of FRG-deletion strains and wild-type strains. In fungi, little is known about connections between volatile organic compound (VOC) formation and developmental stages that are amongst others triggered by fruiting-related genes (FRGs).

Hyphal knots primordia mushroom