New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

Abstract

The strophariaceous basidiomycete Cyclocybe aegerita (synonyms Agrocybe aegerita and A. cylindracea) is one of the most praised cultivated edible mushrooms and is being cultivated at large scale for food production. Furthermore, the fungus serves as a model organism to study fruiting body formation and the production of secondary metabolites during the life cycle of Basidiomycota. By studying the secondary metabolite profiles of C. aegerita, we found several terpenoids in submerged cultures. Aside from the main metabolite, bovistol (1), two new bovistol derivatives B and C (2, 3) and pasteurestin C as a new protoilludane (4) were isolated by preparative HPLC. Their structures were elucidated by mass spectrometry and NMR spectroscopy. The relative configurations of 2–4 were assigned by ROESY correlations, and 3 J H,H coupling constants in the case of 4. Applying quantitative PCR for gene expression validation, we linked the production of bovistol and its derivatives to the respective biosynthesis gene clusters.

Isolation of a gene cluster from Armillaria gallica for the synthesis of armillyl orsellinate–type sesquiterpenoids

“…The enzymes needed to produce several fungal secondary metabolites are encoded by gene clusters, including pleuromutilin produced by Clitopilus pseudopinsitus and Clitopilus passeckerianus (Bailey et al 2016;Alberti et al 2017;Yamane et al 2017;Lin et al 2019), erinacine diterpenoids produced by Hericium erinaceus (Yang et al 2017), and bovistol and pasteurestin C produced by Cyclocybe aegerita (Surup et al 2019). We therefore tested the hypothesis that the biosynthesis of protoilludene-type sesquiterpenoids in A. gallica may also involve a gene cluster and that the isolation of such a cluster would allow the characterization of the corresponding enzymes.…”

Multilocus phylogeny- and fruiting feature-assisted delimitation of European Cyclocybe aegerita from a new Asian species complex and related species

“…With respect to its practical usage, C. aegerita represents an important fungal species cultivated as a choice edible mushroom in many countries, which fruits in consecutive flushes on its spawn substrate (Uhart et al 2008). It also serves as a model basidiomycete to study basidiome (fruiting body, basidiocarp, mushroom) formation (Esser et al 1974;Labarère and Noël 1992;Herzog et al 2016) and to produce biotechnologically relevant enzymes of the UPO-type (unspecific peroxygenases, EC 1.11.2.1;Hofrichter et al 2015Hofrichter et al , 2020, as well as a source of useful natural products like bioactive terpenoids and ribotoxins (Zhao et al 2003;Ngai et al 2005;Kögl et al 2007;Hennicke et al 2019;Surup et al 2019;Tayyrov et al 2019). By using the genome sequence of C. aegerita AAE-3 (Gupta et al 2018), a molecular genetic toolset has recently been developed, now allowing functional genetic approaches to this fungus (Herzog et al 2019).…”

Bovistol B, bovistol D and strossmayerin: Sesquiterpene metabolites from the culture filtrate of the basidiomycete Coprinopsis strossmayeri

“…Bovistol 1 H, 13 C, COSY, HSQC and HMBC NMR spectra were acquired in d4-MeOH (S2-S5 Figs in S1 File). There are 2 methyl groups appearing as a singlet (1.14 and 1.16 ppm) connected to saturated quaternary carbons, while the third methyl group (2.13 ppm), also appears as a singlet, is probably connected to an aromatic ring or substituted carbon-carbon double bond.…”

“…Therefore, the planar structure of 1 is proposed as a dimeric sesquiterpene; the structure of 2 was elucidated as the oxidised form of 1, where the C10 hydroxymethyl group is oxidised to a carboxyl group. 1, previously isolated from C. aegerita, has been characterised by MS and NMR spectroscopy and the relative configurations assigned by ROSEY correlations [13]. The closely related compound bovistol (8) has also undergone extensive structural characterisation [14].…”

“…In our ongoing search for novel antimicrobials, investigations of the culture filtrate of C. strossmayeri were carried out. This led to the isolation of two novel compounds, 2 and 7, as well as the identification of 1 previously isolated from Cyclocybe aegerita [13], the structures of which were determined based on spectroscopic data. Compounds were screened for antimicrobial activity against Bacillus subtilis ATCC 6633, Escherichia coli DH5α and Saccharomyces cerevisiae Y10000.…”