The regular pattern of metabolite changes in mushroom Inonotus hispidus in different growth periods and exploration of their indicator compounds

Inonotus hispidus is a valuable and rare edible and medicinal mushroom with extremely high nutritional and medicinal value. However, there is no holistic insight to elucidate the molecular basis of the differentiated usage and accurate annotation of physiological maturity to fluctuating yields and quality. This study aimed to figure out the fruiting bodies' metabolites change regulation and potential maturating indicators to distinguish different quality I. hispidus. We applied non-targeted ultra-high performance liquid chromatography and high-resolution mass spectrometry combined and with multivariate analysis and analyzed cultivated and wild mushroom I. hispidus in different growth periods (budding, mature and aging). With the fruiting bodies maturating, 1358 metabolites were annotated, 822 and 833 metabolites abundances changed greater than or equal to 1 time from the budding period to the aging period in abundance in cultivated and wild, the total polysaccharides, crude fat, total flavonoids, and total terpenes increased at first and then decreased. Total amino acids, crude protein, and total polyphenols decreased, while the total steroids increased linearly. The change of metabolites showed certain regularity. Metabolic pathways enrichment analysis showed that these metabolites are involved in glycolysis, biosynthesis of amino acids, organic acid metabolism, glycine-serine-and-threonine metabolism, tricarboxylic acid cycle, purine metabolism, and pyrimidine metabolism. In addition, ergosterol peroxide and (22E)-ergosta-4,6,8(14),22-tetraen-3-one can be used as indicator compounds, and their contents increase linearly with the fruiting bodies of I. hispidus’ physiological maturation. This comprehensive analysis will help to evaluate the edible values and facilitate exploitation in mushroom I. hispidus.