Crop rotation is an efficient ecological planting system. However, the effects of different crop rotation patterns on the flavor quality of Pleurotus eryngii at various growth stages remain unclear. This study explored the differences in volatile compounds and the dynamic changes in the aroma of P. eryngii during the primary growth stage, secondary growth stage, and maturation stage under two crop rotation systems: rice followed by oyster mushroom and corn followed by oyster mushroom. Volatile compounds were identified and quantified by headspace solid phase micro-extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Orthogonal partial least squares discriminant analysis (OPLS-DA) and odor activity value (OAV) were applied to analyze the differences in aroma profile and identify key aroma compounds. The results showed that 1-octen-3-ol, 3-octanone, n-heptane, methanethiol, and 3-octanol were the major aroma components of P. eryngii. The differences in the contents of volatile compounds primarily accounted for the distinct volatile characteristics observed at different growth stages. Specifically, the contents of 3-methyl-2-buten-1-ol, 3-benzyl alcohol, and 1-hexadecene overall increased during the growth of P. eryngii under rice rotation, showing an increasing and then decreasing trend. In contrast, the contents of 1-octene, styrene, and 2-phenyl-1-propene significantly increased during the growth of P. eryngii under corn rotation. Furthermore, crop rotation systems significantly impacted the aroma of P. eryngii, with the total volatile compound concentration in P. eryngii grown under rice rotation being higher when compared with the one grown under corn rotation. Based on the OAV of volatile compounds at different growth stages for both crop rotation systems, 13 key aroma compounds were identified in the rice rotation system and 10 key aroma compounds in the corn rotation system. These identified volatile compounds could serve as potential biomarkers for distinguishing P. eryngii at various growth stages.

Boletus aereus have biological effects such as anti-inflammatory, antioxidant and immunomodulatory effects. As medicines and functional foods, Boletus aereus has a long history of application. In order to explore the immunomodulatory mechanism of Boletus aereus polysaccharide (BAP) in the intestinal tract, the present study was conducted to construct a mouse model of colitis induced by LPS, and the preventive mechanism of Boletus aereus extract on LPS-induced intestinal inflammation in rats was analyzed by histopathological examination and biochemical analysis. Meanwhile, the immunomodulatory mechanisms were analyzed in combination with metabolomics and gut microbiomics. We found that BAP effectively reduced the levels of pro-inflammatory factors IL-6 and TNF-α and increased the levels of anti-inflammatory factor IL-10 in the serum of mice, and BAP suppressed the expression of TLR4/NF-ĸB/MAPK inflammatory signaling pathway in the colonic tissues, inhibited the expression of inflammatory vesicle NRLP3, and promoted the expression of NRF2/HO-1 signaling pathway, and elevated the SOD, T- AOC, and T-AOC levels. BAP decreased the expression of the TGF/Smad signaling pathway and decreased the expression of the fibrosis factors Collagen I Collagen III, α-SMA. The results indicated that Boletus edulis extract may exert immunomodulatory function by inhibiting TLR4/NF-ĸB/MAPK signaling pathway,and enhance the anti-oxidative stress ability by promoting the expression of NRF2/HO-1 signaling pathway. BAP altered the composition of gut microbiota in LPS-induced mice. In addition, Spearman's correlation coefficient showed a significant correlation between serum tyrosine metabolic pathway and gut microbiota species. The changes in gut microbiota and serum metabolites may partially explain the protective effect of BAP against colitis. In conclusion, these results suggest that BAP may be involved in the prevention of colitis disease at multiple levels, and also provide a theoretical basis for the development of Boletus aereus as an adjunctive functional edible for enteropathy.