Liquid Chromatography-Mass Spectrometry-Based Metabolomic Analysis of Metabolites and Metabolic Pathways of Selenium-Enriched Auricularia auricula

Auricularia auricula was selenized by adding exogenous selenium to the compost. The effect of selenization on the dynamic changes of metabolic pathways and metabolites in A. auricula was investigated using liquid chromatographymass spectrometry (LC-MS)-based metabolomics combined with different multivariate statistical analyses such as principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and hierarchical cluster analysis. Totally 669 metabolites were identified in A. auricula, inorganic selenized A. auricula grown on sodium selenite, and organic selenized A. auricula grown on selenium-rich corn straw. A total of 228 differential metabolites (DEMs) were obtained in A. auricula vs inorganic selenized A. auricula, and 267 DEMs in A. auricula vs organic selenized A. auricula. It was found that selenization had a great effect on the contents of organic acids and their derivatives, lipids and lipid-like molecules in A. auricula, and the effect of organic selenization was more pronounced. Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis found that selenization had a significant effect on lipid and amino acid metabolism. These results showed that lipid metabolism, amino acid metabolism and the biosynthesis of other secondary metabolites in A. auricula changed significantly after selenization, which had a significant effect on lipids, amino acids and other metabolites in A. auricula. This indicated that selenization affected the nutritional composition and flavor quality of A. auricula.