Journal of Plant Biochemistry & Physiology
Open Access

Metabolic Responses of Tea Leaves

Basel S^{* *}Correspondence: Basel S, Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria, Syria, Email:

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Introduction

It is well-known that anaerobic treatment has been considered as a utility process to accumulate γ-aminobutyric acid (GABA) in tea leaves. In this article, the non-volatile differential compounds in picked-tea leaves between filled-N₂ treatment and filled-CO₂ treatment were compared in metabolic profiles and dynamic changes via ultrahigh performance liquid chromatography linked to a hybrid quadrupole orthogonal time-of-flight mass spectrometer (UPLC-QTOF-MS).

Multivariate analysis and heat map of hierarchical clustering analysis indicated that filled-N₂ treatment resulted in a wider range of metabolic perturbation than filled-CO₂ treatment, but GABA accumulates faster and more significantly under filled-CO₂ treatment than other treatment.

The differential metabolites in anaerobic treatment were mainly reflected in the levels of glucose metabolism and amino acid metabolism, and the main differential pathway included the glyoxylate metabolism pathway, galactose metabolism, and phenylalanine metabolism. These metabolomics analyses were also evaluated to illuminate the physiological adaptive strategies of tea adopted to tolerate certain anaerobic stress types.

Rising atmospheric carbon dioxide, an important driver of climatchange, has multifarious effects on crop yields and quality. Despite tremendous progress in understanding the mechanisms of plant responses to elevated CO₂, only a few studies have examined the CO₂-enrichment effects on tea plants.

Tea, a non-deciduous woody perennial plant, operates massive physiologic, metabolic and transcriptional reprogramming to adapt to increasing CO₂. Tea leaves elevate photosynthesis when grown at CO₂–enriched environment which is attributed to increased maximum carboxylation rate of RuBisCO and maximum rates of RuBP regeneration.

Elevated CO₂-induced photosynthesis enhances the energy demand which triggers respiration. Stimulation of photosynthesis and respiration by elevated CO₂ promotes biomass production. Moreover, elevated CO₂ increases total carbon content, but it decreases total nitrogen content, leading to an increased ratio of carbon to nitrogen in tea leaves.

Elevated CO₂ alters the tea quality by differentially influencing the concentrations and biosynthetic gene expression of tea polyphenols, free amino acids, catechins, theanine, and caffeine. Signalling molecules salicylic acid and nitric oxide function in a hierarchy to mediate the elevated CO2-induced flavonoid biosynthesis in tea leaves.