都匀毛尖台地茶树和老茶树鲜叶次生代谢产物差异分析OA

[Objective]This study aimed to analyze secondary metabolic differences in fresh leaves between Duyun Maojian terrace tea trees and old tea trees,providing theoretical basis for appropriate utilization and processing method se-lection of Duyun Maojian ancient tea tree resources.[Method]Untargeted metabolomics technology was used to measure the secondary metabolites in fresh leaves of Duyun Maojian terrace tea trees and old tea trees.METLIN database were used to perform qualitative analysis of metabolites.Multivariate statistical analysis methods were used to perform quantita-tive analysis and differential screening of metabolites.KEGG metabolic pathway enrichment analysis was carried out for significantly differential metabolites.[Result]The secondary metabolites between Duyun Maojian terrace tea trees and old tea trees were markedly different,and principal component analysis(PCA)could clearly distinguish the individuals of two tea trees.Ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-QTOF-MS)was utilized to detect 296 metabolites.Orthogonal partial least squares discriminant analysis(OPLS-DA)was used to detect 27 significantly differential metabolites based on the standard of variable importance in projection(VIP)≥1 and|log2 Fold Change|≥1(P<0.05,the same below),including 6 amino acids and the derivatives,6 polyphe-nols,5 purine bases and the nucleosides,4 aromatic substances,3 heterocyclic compounds,1 sugar substance,1 vita-min substance,and 1 amide substance.Compared to terrace tea trees,fresh leaves of old tea trees contained 15 up-regulated significantly differential metabolites,primarily amino acids and the derivatives,sugars,and catechins,as well as 12 down-regulated metabolites,mainly polyphenols,purine alkaloids,and nucleosides.KEGG pathway analysis showed that these 27 significantly differential metabolites were mainly involved in the phenylalanine biosynthesis path-way,flavonoid biosynthesis pathway,amino acid metabolism pathway,and purine metabolism pathway.Substances af-fecting tea quality such as ideain,phenylacetaldehyde,caffeine,and trans-zeatin-riboside-O-glucoside showed higher contents in fresh leaves of terrace tea trees,while substances such as chrysantherol,amino acids and the derivatives,α,β-trehalose,and epicatechin gallate had higher contents in fresh leaves of old tea trees.[Conclusion]Based on the diffe-rences and proportional coordination of 27 significantly differential metabolites in fresh leaves of Duyun Maojian tea trees at different ages,green tea processed from Duyun Maojian old tea trees is more refreshing and sweet,and black tea pro-cessed from terrace tea trees is richer and mellower.