Abstract: In order to investigate the differences in volatile metabolites between Guizhou local dried chili peppers and other varieties, fresh ‘Jizhua’ chili peppers (GZ-JZ), a local variety from Congjiang, Guizhou, and four other cluster-type advanced-generation inbred lines (7013-1-1, GJH18-69, Gy17-14, and SZ14-1) were selected and systematically analyzed for differences in the composition of volatile metabolites using widely targeted metabolomics based on gas chromatography-mass spectrometry (GC-MS). The results showed that a total of 885 volatile flavor substances were identified, primarily including 208 terpenes, 154 esters, 91 ketones, 82 alcohols, 82 heterocyclic compounds, 57 hydrocarbons, 54 aldehydes, 40 acids, and 37 phenols. GZ-JZ exhibited the highest diversity and total content of metabolites. By using the cutoff of variable importance in projection (VIP) > 1 with P < 0.05, 108 common differential metabolites were selected, predominantly hydrocarbons (30.2%), esters (20.8%), and terpenoids (18.9%). Results from principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) indicated significant differences between GZ-JZ and the other four inbred lines, whereas the differences among those four varieties were not significant, with terpenoids and esters being the major differential substances. Further, we identified 53 common core differential metabolites, including 16 hydrocarbons, 10 terpenoids, and 11 esters. The relative contents of these differential metabolites were generally higher in GZ-JZ than in the other varieties. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the key differential metabolic pathways were mainly involved in core carbon and energy metabolism processes, such as glyoxylate and dicarboxylate metabolism, carbon metabolism, C5-branched dibasic acid metabolism, and N-glycan biosynthesis, providing a foundation for the synthesis of secondary metabolites. GZ-JZ exhibited significant upregulation in pathways related to the synthesis of aroma and flavor substances, including terpenoid backbone biosynthesis, amino acid biosynthesis, and various plant secondary metabolic pathways. This study provides a theoretical basis and data support for elucidating the characteristics of volatile metabolites and varietal differences in Guizhou local chili peppers.

Key words: Guizhou local chili pepper varieties; widely targeted metabolomics; volatile metabolites; differential analysis; metabolic pathways