Light Intensity Modulates the Effect of Phosphate Limitation on Carbohydrates, Amino Acids, and Catechins in Tea Plants (Camellia sinensis L.)

Abstract

Metabolites are major contributors to the quality of tea that are regulated by various abiotic stresses. Light intensity and phosphorus (P) supply affect the metabolism of tea plants. However, how these two factors interact and mediate the metabolite levels in tea plants are not fully understood. The present study investigated the consequences of different light intensity and P regimes on the metabolism of carbohydrates, amino acids, and flavonoids in the Fengqing tea cultivar. The leaves and young shoots were subjected to untargeted metabolomics analysis by two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOF/MS), ultra-performance liquid chromatography-quadrupole-TOF/MS (UPLC–Q–TOF/MS), and targeted analysis by high-performance liquid chromatography (HPLC) along with quantification of gene expression by quantitative real time-PCR (qRT–PCR). The results from young shoots showed that amino acids, pentose phosphate, and flavonol glycosides pathways were enhanced in response to decreasing light intensities and P deficiency. The expression of the genes hexokinase 1, ribose 5-phosphate isomerase A (RPIA), glutamate synthetase 1 (GS1), prolyl 4-hydroxylase (P4H), and arginase was induced by P limitation, thereafter affecting carbohydrates and amino acids metabolism, where shading modulated the responses of transcripts and corresponding metabolites caused by P deficiency. P deprivation repressed the expression of Pi transport, stress, sensing, and signaling (SPX2) and induced bidirectional sugar transporter (SWEET3) and amino acid permeases (AAP) which ultimately caused an increase in the amino acids: glutamate (Glu), proline (Pro), and arginine (Arg) under shading but decreased catechins [epicatechingallate (ECG) and Gallic acid, GA] content in young shoots.

Depicting the genetic and metabolic panorama of chemical diversity in the tea plant

“…The rich taste, flavour and health benefits of tea, coupled with its regional cultural significance, have made it a highly popular beverage. Metabolites produced by crops are critical for their own growth and development and also for meeting various demands of humans (Brotman et al ., 2021; Kc et al ., 2021; Li et al ., 2022a; Sreenivasulu and Fernie, 2022; Tiozon et al ., 2022; Vollmer et al ., 2018). The fresh leaves of tea plants contain a variety of metabolites, as reported previously and investigated in this study, which are key components and important underpinning to determine the final quality of tea (i.e., various tastes, flavours and health benefits) after being processed into consumed tea (Wei et al ., 2018; Yang et al ., 2013; Yu et al ., 2020).…”

Effect of Interactions between Phosphorus and Light Intensity on Metabolite Compositions in Tea Cultivar Longjing43

“…In addition, the concentration of l -glutamate was higher in young shoots than in mature leaves, indicating the transportation of Glu from source to sink. It has been reported GSTb has a weak affinity for epicatechin which was reduced by P deficiency, but the gallate concentration increases in young shoots [ 4 , 7 ]. Our results show that the epicatechin gallate increased in young shoots due to P deficiency, in agreement with previous findings.…”

“…Corresponding chromatogram peaks were compared to the National Institute of Standards and Technology (NIST, FairCom Co., Gaithersburg, MD, USA), and peaks were annotated from accurate mass measurements using online metabolite databases. The metabolites were identified based on the actual mass, retention time, and isotopic distribution, and accurate mass measurements were confirmed from the Metlin online web-based database and our published literature [ 4 ].…”

“…These shade-tolerant plants possess beneficial bioactive tea components [ 2 ] that are classified as primary and secondary metabolites and determine the product quality [ 3 ]. Carbohydrates, amino acids, and flavonoids are among the highest quality components [ 4 , 5 ]. Thousands of metabolites present in each class are differently expressed due to various environmental and mineral effects [ 6 ].…”

“…The most abundant amino acids in tea are theanine (Thea), glutamine (Gln), glutamic acid (Glu), and arginine (Arg) [ 30 , 31 ]. The coefficient value obtained in one study revealed that Thea, Gln, and Arg are the major contributors to high-ranking teas, whereas aspartic acid (Asp) and alanine (Ala) are major contributors to low-ranking teas [ 4 ]. Plants regulate the carbon flux toward aromatic amino acid biosynthesis at the transcriptional and post transcriptional levels [ 5 ].…”