Integrated proteomic and metabolomic analyses reveal the importance of aroma precursor accumulation and storage in methyl jasmonate-primed tea leaves

Abstract

In response to preharvest priming with exogenous methyl jasmonate (MeJA), tea plants adjust their physiological behavior at the molecular level. The whole-organism reconfiguration of aroma formation from the precursor to storage is poorly understood. In this study, we performed iTRAQ proteomic analysis and identified 337, 246, and 413 differentially expressed proteins in tea leaves primed with MeJA for 12 h, 24 h, and 48 h, respectively. Furthermore, a total of 266 nonvolatile and 100 volatile differential metabolites were identified by utilizing MS-based metabolomics. A novel approach that incorporated the integration of extended self-organizing map-based dimensionality was applied. The vivid time-scale changes tracing physiological responses in MeJA-primed tea leaves are marked in these maps. Jasmonates responded quickly to the activation of the jasmonic acid pathway in tea leaves, while hydroxyl and glycosyl jasmonates were biosynthesized simultaneously on a massive scale to compensate for the exhausted defense. The levels of α-linolenic acid, geranyl diphosphate, farnesyl diphosphate, geranylgeranyl diphosphate, and phenylalanine, which are crucial aroma precursors, were found to be significantly changed in MeJA-primed tea leaves. Green leaf volatiles, volatile terpenoids, and volatile phenylpropanoids/benzenoids were spontaneously biosynthesized from responding precursors and subsequently converted to their corresponding glycosidic forms, which can be stably stored in tea leaves. This study elucidated the physiological response of tea leaves primed with exogenous methyl jasmonate and revealed the molecular basis of source and sink changes on tea aroma biosynthesis and catabolism in response to exogenous stimuli. The results significantly enhance our comprehensive understanding of tea plant responses to exogenous treatment and will lead to the development of promising biotechnologies to improve fresh tea leaf quality.

Effects of Preharvest Methyl Jasmonate and Salicylic Acid Treatments on Growth, Quality, Volatile Components, and Antioxidant Systems of Chinese Chives

“…Studies have also shown that MeJA can affect the biosynthesis of fruit components, such as carotene, chlorophyll, and vitamins (Saniewski and Czapski, 1983;Pérez et al, 1993;Wolucka et al, 2005). In addition, Shi et al (2021) showed that MeJA induced the accumulation of tea (Camellia sinensis L.) aroma precursors and improved the quality of fresh leaves. Moreover, it has been observed that the application of MeJA significantly enhanced the flavor quality of fruits and vegetables, such as peaches (Prunus persica L. Batsch), strawberries (Fragaria × ananassa Duch.…”

Untargeted Metabolomics and Transcriptomics Reveal the Mechanism of Metabolite Differences in Spring Tender Shoots of Tea Plants of Different Ages

“…Omics technology provides a powerful tool for tea plant research, which is characterized by its high throughput, high sensitivity, and systematic nature [ 23 ]. Metabolomics can be used for qualitative and quantitative analysis of low-molecular-weight substances produced in tea plants in a specific period [ 24 ].…”

Enhanced volatile emissions and anti-herbivore functions mediated by the synergism between jasmonic acid and salicylic acid pathways in tea plants

“…The volatile compounds released by fresh tea leaves are responsible for tea aroma [ 59 ]. Previous studies revealed that the aroma quality of black and oolong teas can be improved by spraying the leaves of tea plants with MeJA, which results in increased emission of desirable aroma compounds, including terpenes and aromatic compounds [ 58 , 60 ]. Thus, the changes to volatile emissions induced by the JA–SA synergism may be exploited to improve tea processing.…”