Metabolic Flux Enhancement and Transcriptomic Analysis Displayed the Changes of Catechins Following Long-Term Pruning in Tea Trees (Camellia sinensis)

Abstract

The tea tree is a perennial woody plant, and pruning is one of the most crucial cultivation measurements for tea plantation management. To date, the relationship between long-term pruning and metabolic flux enhancement in tea trees has not been studied. In this research, 11-year-old pruned tea trees from four different cultivars were randomly selected for transcriptome analysis and characteristic secondary metabolite analysis together with controls. The findings revealed that epigallocatechin gallate (EGCG) accumulation in pruned tea trees was significantly higher than that in unpruned tea trees. SCPL1A expression (encoding a class of serine carboxypeptidase), which has been reported to have a catalytic ability during EGCG biosynthesis, together with LAR, encoding leucoanthocyanidin reductase, was upregulated in the pruned tea trees. Moreover, metabolic flux enhancement and transcriptome analysis revealed low EGCG accumulation in the leaves of unpruned tea trees. Because of the bitter and astringent taste of EGCG, these results provide a certain understanding to the lower bitterness and astringency in teas from "ancient tea trees", growing in the wild with no trimming, than teas produced from pruned plantation trees.

Unpruning improvement the quality of tea through increasing the levels of amino acids and reducing contents of flavonoids and caffeine

“…The dominate catechin was EGCG, with a content of (17.66 ± 0.75)– (19.62 ± 5.37) mg/g in UPTT and (21.60 ± 2.18)– (24.48 ± 2.86) mg/g in PTT. Both the sum content of catechins and the level of EGCG were higher in PTTs than in UPTTs, which is consistent with previous studies ( 27 ).…”

A novel adenylate isopentenyltransferase 5 regulates shoot branching via the ATTTA motif in Camellia sinensis

“…Pruning is an essential agronomic practice in tea cultivation [ 39 , 40 ]. In this study, the increased expression of total CsA-IPT5 transcripts, 5AS3 and 3AS2, increased protein expression of CsA-IPT5, as well as increased concentrations of t Z and t ZR in the stem node induced by pruning treatment were shown to be positively correlated.…”

Effects of Long-Term Non-Pruning on Main Quality Constituents in ‘Dancong’ Tea (Camellia sinensis) Leaves Based on Proteomics and Metabolomics Analysis

“…Content of gallic acid (GA), the precursor of ester catechin synthesis, was also significantly higher in leaves of pruned tea plants. Catechins are biosynthesized through the flavonoid and phenylpropanoid pathways; further, phenylalanine ammonia lyase (PAL) is the first key enzyme responsible for catalyzing L-phenylalanine deamination to trans-cinnamic acid [19]. Our proteomic analysis identified 35 proteins involved in catechin biosynthesis, eight of which were downregulated (fold change < 0.85, p < 0.05) in leaves of long-term unpruned tea plants, while none of the other 27 proteins were upregulated significantly (Table 1 and Table S2).…”

“…For example, the synthesis of indole-3-acetonitrile and menaquinone increased in pruned tea plants and enhanced shoot growth and development [17]. Similarly, EGCG concentration was much higher in pruned than in unpruned tea trees, and serine carboxypeptidase was upregulated for biosynthesis of EGCG in pruned tea plants [19]. Different concentrations of EGCG in long-term pruned and unpruned tea plants account for differences in the degree of bitterness and astringency in the corresponding tea products.…”