Wild edible Termitomyces mushrooms are popular in Southwest China and umami is important flavor qualities of edible mushrooms. This study aimed to understand the umami taste of Termitomyces intermedius and Termitomyces aff. bulborhizus. Ten umami peptides from aqueous extracts were separated using a Sephadex G-15 gel filtration chromatography. The intense umami fraction was evaluated by both sensory evaluation and electronic tongue. They were identified as KLNDAQAPK, DSTDEKFLR, VGKGAHLSGEH, MLKKKKLA, SLGFGGPPGY, TVATFSSSTKPDD, AMDDDEADLLLLAM, VEDEDEKPKEK, SPEEKKEEET and PEGADKPNK. Seven peptides, except VEDEDEKPKEK，SPEEKKEEET and PEGADKPNK were selectively synthesized to verify their taste characteristics. All these 10 peptides had umami or salt taste. The 10 peptides were conducted by molecular docking to study their interaction with identified peptides and the umami taste receptor T1R1/T1R3. All these 10 peptides perfectly docked the active residues in the T1R3 subunit. Our results provide theoretical basis for the umami taste and address the umami mechanism of two wild edible Termitomyces mushrooms.

The genus Armillaria has high edible and medical values, with zones of antagonism often occurring when different species are paired in culture on agar media, while the antagonism-induced metabolic alteration remains unclear. Here, the metabolome of mycelial exudates of two Chinese Armillaria biological species, C and G, co-cultured or cultured separately was analysed to discover the candidate biomarkers and the key metabolic pathways involved in Armillaria antagonists. A total of 2,377 metabolites were identified, mainly organic acids and derivatives, lipids and lipid-like molecules, and organoheterocyclic compounds. There were 248 and 142 differentially expressed metabolites between group C-G and C, C-G, and G, respectively, and fourteen common differentially expressed metabolites including malate, uracil, Leu-Gln-Arg, etc. Metabolic pathways like TCA cycle and pyrimidine metabolism were significantly affected by C-G co-culture. Additionally, 156 new metabolites (largely organic acids and derivatives) including 32 potential antifungal compounds, primarily enriched into biosynthesis of secondary metabolites pathways were identified in C-G co-culture mode. We concluded that malate and uracil could be used as the candidate biomarkers, and TCA cycle and pyrimidine metabolism were the key metabolic pathways involved in Armillaria antagonists. The metabolic changes revealed in this study provide insights into the mechanisms underlying fungal antagonists.

The production of a distinct profile of volatile organic compounds plays a crucial role in the ecology of hypogeous Ascomycetes, and is also key to their gastronomic relevance. In this study, we explored the aroma components of two rarely investigated Chinese desert truffles, namely Mattirolomyces terfezioides and Choiromyces cerebriformis, using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Our investigation revealed the significant presence of sulphur-containing volatiles in the aroma of M. terfezioides but not in C. cerebriformis. We discussed available information on the distribution of these interesting truffles in China and their use as choice food by local people.

Aroma is central to the worldwide success of truffles as gourmet food and the high prices paid for these edible mushrooms. In this study, volatile organic compounds (VOCs) from fruiting bodies of two Chinese truffles of commercial relevance, Tuber indicum and Tuber pseudohimalayense, were analyzed using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). We aimed to characterize the aroma profile and determine whether it would be influenced by provenance and stage of maturation. We thus collected and analyzed young, middle mature and mature fruiting bodies of each species from different locations in Yunnan and Sichuan provinces, located in southwestern China. Overall, 76 VOCs were identified, belonging to different chemical classes, i.e. alcohols and phenols, aldehydes and ketones, benzenes and methoxy compounds, hydrocarbons and amines. A large number of volatiles identified in T. indicum and T. pseudohimalayense are reported here for the first time for these truffles. While more than 50% of identified VOCs were produced by both truffle species, considerable differences were present in the aroma profiles of fruiting bodies collected at various maturation stages, revealing a dynamic pattern in the biosynthesis of VOCs. Furthermore, truffles of different provenance had distinct proportions of volatile constituents, suggesting that, besides genetic factors, edaphic and microclimatic conditions influence the synthesis of VOCs in a complex manner.