AUTHOR=Zhou Zi-wei , Wu Qing-yang , Ni Zi-xin , Hu Qing-cai , Yang Yun , Zheng Yu-cheng , Bi Wan-jun , Deng Hui-li , Liu Zhen-zhang , Ye Nai-xin , Lai Zhong-xiong , Sun Yun 

TITLE=Metabolic Flow of C6 Volatile Compounds From LOX-HPL Pathway Based on Airflow During the Post-harvest Process of Oolong Tea

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.738445

DOI=10.3389/fpls.2021.738445

ISSN=1664-462X

ABSTRACT=Aroma is one of the essential quality indicators of oolong tea. C6 acid and its derivative esters are important components in fatty acid(FA)-derived volatile in oolong tea. However, the formation and regulation mechanism of C6 acid during the post-harvest process of oolong tea remained unclear. To gain better insights into the molecular and biochemical mechanisms behind C6-compounds of oolong tea, a combined analysis of ADH activity, CsADH2 key genes expression and FA-derived metabolome during the psot-harvest process of oolong tea was performed for the first time, complemented with CsHIP (Hypoxia induced protein conserved region) genes expression analysis. VFAD-targeted metabolomics analysis by head-space solid-phase microextraction gas chromatography time-of-flight mass spectrometry (HS-SPEM-GC-TOF MS), (Z)-3-hexen-1-ol content increased after each turn over, while hexanoic acid content showed the opposite trend. Both the activity of ADH and the expression level of CsADH gene in oxygen-deficitt-turnover tea leaves(ODT) were higher than that of oxygen- turnover tea leaves(OT). The C6-alcohol-derived esters content of OT were significantly higher than that of the ODT, but the C6-acid-derived esters content were to the contrary. Moreover, we screened and analyzed the HIP genes family, and found that ODT treatment could significantly promote the up-regulation of CsHIG4 and CsHIG6 gene expression. Our results show that the formation mechanism of oolong tea aroma quality mediated by airflow factor in term of LOX pathway, which provides a theoretical reference for quality control in post-harvest process of oolong tea in the future.