The key role of LeuRS in the development of the cleistothecium and the metabolization of the flavor during the fermentation of dark tea with Aspergillus montevidensis

Post-fermented tea has multiple health-promoting efficacy; however, the molecular mechanisms of quality formation remain largely unknown. Here, we found that leucyl-tRNA synthetase (LeuRS) is essential for the formation of ‘golden flowers' in dark teas fermented by A. montevidensis. Metabolomics based on UHPLC-Q-TOF/MS revealed 67, 130, and 98 differential metabolites in the compared groups of fermented teas by wide-type strains (WT)/by ΔleuRS mutants (MT) at 3, 9 and 15 days, respectively. These differential metabolites consisted mainly of flavonoids, sugars, organic acids, and fatty acids. Transcriptome analysis showed that hundreds of genes were significantly differentially expressed compared to WT with MT, which were mainly involved in KEGG pathways such as starch and sucrose metabolism, degradation of aromatic compounds, amino acid metabolism and lipid metabolism. These findings highlighted that LeuRS plays a crucial role in the development of the fungal cleistothecium and the flavor formation of the post-fermented teas with A. montevidensis.