A New Species Agrocybe striatipes, also a Newly Commercially Cultivated Mushroom with Highly Nutritional and Healthy Values

**Background:** The genus Agrocybe (family Strophariaceae) contains saprophytic mushrooms distributed across temperate regions of Asia, Europe, and North America. While the related genus Cyclocybe includes several successfully cultivated edible species (e.g., C. cylindracea, the widely cultivated 'Chashugu'), only one Agrocybe species—A. praecox—had been domesticated prior to this study. The authors sought to characterize a newly collected Agrocybe specimen from Sichuan Province, China, using morphological and molecular phylogenetic methods, and to evaluate its potential for commercial cultivation and nutritional value.

**Methods:** Mushroom specimens were collected from FuAn Village, Xingwen County, Yibin City, Sichuan Province (28.36 N, 105.12 E). Morphological characterization followed standard protocols using 5% KOH staining, with over 20 measurements taken for microscopic features. Molecular phylogenetic analysis used ITS and nrLSU sequences; six ITS and six nrLSU sequences were newly generated. Maximum likelihood (RAxmlGUI 1.3, GTRGAMMA model, 1000 bootstrap replicates) and Bayesian inference (MrBayes v3.2.6, 2,000,000 generations) analyses included 95 samples representing 23 Agrocybe species. Nutritional composition was analyzed from dried artificially cultivated fruiting bodies using an automatic amino acid analyzer (L-8800) and atomic-fluorescence photometer (AFS3000) under China's National Food Safety Standard System. Heavy metals (Pb, Cd, Hg, As) were determined by atomic fluorescence spectrometry. Bioactive compounds were analyzed by HPLC (Agilent 1200) on a C18 column with methanol/water gradient elution, and structures determined by ¹H and ¹³C NMR.

**Key Results:** Phylogenetic analysis placed the new species in Clade I of Agrocybe, sister to A. smithii, with strong support (99% bootstrap/1.0 Bayesian posterior probability). The species is named Agrocybe striatipes (holotype HMAS286942), characterized by a yellowish ochraceous-brown pileus (18–45 mm diameter), deeply striate-sulcate stipe (65–125 × 30–80 mm), absence of an annulus, and basidiospores measuring 8.1–10 × 5.2–6.9 μm (Qm = 1.4 ± 0.1). Nutritional analysis of cultivated fruiting bodies revealed: protein 5.66 g/100g (nearly three times that of A. praecox at 2.05 g/100g), crude polysaccharide 0.75 g/100g, calcium 78.5 mg/kg (vs. 33.4 mg/kg in A. praecox), zinc 6.87 mg/100g, selenium 0.048 mg/100g, vitamin D 44.1 μg/100g (vs. 2 μg/100g in A. praecox), vitamin B1 0.0850 mg/100g, and vitamin B2 0.333 mg/100g. Total amino acid content was 4.14 g/100g (17 amino acids detected), with essential amino acids comprising 33% of total (E/T = 0.33). Notably, gamma-aminobutyric acid (GABA) was detected at 0.017 g/100g, which was not reported in comparator species. Heavy metal analysis showed all values within safe limits: Pb 0.0262 mg/kg (limit ≤0.5), Cd 0.047 mg/kg (≤0.2), As 0.036 mg/kg (≤0.5), Hg 0.053 mg/kg (≤0.1). Bioactive compound analysis identified ergosterol as the main compound in the ethyl acetate fraction (retention time 40.0 min), confirmed by ¹H and ¹³C NMR.

**Clinical Implications:** A. striatipes represents only the second Agrocybe species successfully domesticated for cultivation. Its high protein content, rich mineral profile (especially calcium and zinc), and exceptionally high vitamin D content (44.1 μg/100g) suggest potential benefits for bone health, immune function, and nutritional supplementation in elderly populations and growing children. The presence of ergosterol, a precursor to vitamin D2, may further support calcium and phosphorus absorption. The absence of heavy metal contamination supports food safety. The authors recommend combining A. striatipes with other foods to achieve complementary amino acid and mineral balance. Further research into polysaccharide extraction and medicinal properties is warranted.