The Dynamic Change in Aromatic Compounds and Their Relationship with CsAAAT Genes during the Post-Harvest Process of Oolong Tea

• Published in: Metabolites Vol. 13; no. 7; p. 868
• Main Authors: Zhou, Ziwei, Wu, Qingyang, Rao, Hongting, Cai, Liewei, Zheng, Shizhong, Sun, Yun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.07.2023; MDPI
• Subjects: Amino acids; Aromatic compounds; Benzoic acid; CsAAAT gene; Enzymes; Genomes; Harvest; Ions; Manufacturing; manufacturing process; Mass spectrometry; Metabolism; Metabolites; Metabolomics; Methods; oolong tea; Phenylalanine; Phenylethyl alcohol; Phenylpropanoids; Phylogenetics; Scientific imaging; Tea; Transcriptomes; VOCs; Volatile organic compounds; volatile phenylpropanoids/benzenoids; China; manufacturing process; oolong tea; CsAAAT gene; volatile phenylpropanoids/benzenoids
• ISSN: 2218-1989; 2218-1989
• DOI: 10.3390/metabo13070868

Formed by L-phenylalanine (L-phe) ammonia under the action of aromatic amino acid aminotransferases (AAATs), volatile benzenoids (VBs) and volatile phenylpropanoids (VPs) are essential aromatic components in oolong tea ( ). However, the key VB/VP components responsible for the aromatic quality of oolong tea need to be revealed, and the formation mechanism of VBs/VPs based on AAAT branches during the post-harvest process of oolong tea remains unclear. Therefore, in this study, raw oolong tea and manufacturing samples were used as the test materials, and targeted metabolomics combined with transcriptome analysis was also conducted. The results showed that thirteen types of VBs/VPs were identified, including nine types of VPs and four types of VBs. Based on the OAV calculation, in raw oolong tea, 2-hydroxy benzoic acid methyl ester and phenylethyl alcohol were identified as key components of the aromatic quality of oolong tea. As for the results from the selection of related genes, firstly, a total of sixteen candidate genes were selected and divided into two sub-families ( and ); then, six key genes closely related to VB/VP formation were screened. The upregulation of the expression level of -type genes may respond to light stress during solar-withering as well as the mechanical force of turnover. This study can help to understand the formation mechanism of aromatic compounds during oolong tea processing and provide a theoretical reference for future research on the formation of naturally floral and fruity aromas in oolong tea.