The epitranscriptomic mark N⁶-methyladenosine (m⁶A), which is the predominant internal modification in RNA, is important for plant responses to diverse stresses. Multiple environmental stresses caused by the tea-withering process can greatly influence the accumulation of specialized metabolites and the formation of tea flavor. However, the effects of the m⁶A-mediated regulatory mechanism on flavor-related metabolic pathways in tea leaves remain relatively uncharacterized. We performed an integrated RNA methylome and transcriptome analysis to explore the m⁶A-mediated regulatory mechanism and its effects on flavonoid and terpenoid metabolism in tea (Camellia sinensis) leaves under solar-withering conditions. Dynamic changes in global m⁶A level in tea leaves were mainly controlled by two m⁶A erasers (CsALKBH4A and CsALKBH4B) during solar-withering treatments. Differentially methylated peak-associated genes following solar-withering treatments with different shading rates were assigned to terpenoid biosynthesis and spliceosome pathways. Further analyses indicated that CsALKBH4-driven RNA demethylation can directly affect the accumulation of volatile terpenoids by mediating the stability and abundance of terpenoid biosynthesis-related transcripts and also indirectly influence the flavonoid, catechin, and theaflavin contents by triggering alternative splicing-mediated regulation. Our findings revealed a novel layer of epitranscriptomic gene regulation in tea flavor-related metabolic pathways and established a link between the m⁶A-mediated regulatory mechanism and the formation of tea flavor under solar-withering conditions.
RNA/metabolism* ; Epigenome ; Plant Proteins/metabolism* ; Plant Leaves/metabolism* ; Camellia sinensis/metabolism* ; Flavonoids ; Terpenes/metabolism* ; Tea/metabolism* ; Gene Expression Regulation, Plant

Oolong tea is a semi-fermented tea with strong flavor, which is widely favored by consumers because of its floral and fruity aroma as well as fresh and mellow taste. During the processing of oolong tea, withering is the first indispensable process for improving flavor formation. However, the molecular mechanism that affects the flavor formation of oolong tea during withering remains unclear. Transcriptome sequencing was used to analyze the difference among the fresh leaves, indoor-withered leaves and solar-withered leaves of oolong tea. A total of 10 793 differentially expressed genes were identified from the three samples. KEGG enrichment analysis showed that the differentially expressed genes were mainly involved in flavonoid synthesis, terpenoid synthesis, plant hormone signal transduction and spliceosome pathways. Subsequently, twelve differentially expressed genes and four differential splicing genes were identified from the four enrichment pathways for fluorescence quantitative PCR analysis. The results showed that the expression patterns of the selected genes during withering were consistent with the results in the transcriptome datasets. Further analysis revealed that the transcriptional inhibition of flavonoid biosynthesis-related genes, the transcriptional enhancement of terpenoid biosynthesis-related genes, as well as the jasmonic acid signal transduction and the alternative splicing mechanism jointly contributed to the flavor formation of high floral and fruity aroma and low bitterness in solar-withered leaves. The results may facilitate better understanding the molecular mechanisms of solar-withering treatment in flavor formation of oolong tea.
Camellia sinensis/genetics* ; Gene Expression Profiling ; Plant Leaves ; Plant Proteins/metabolism* ; Taste ; Tea ; Transcriptome/genetics*

Objective To investigate the correlation of uric acid(UA) level and the circadian rhythm of blood pressure in hypertensive patients. Methods Among the individuals who presented to the cardiology clinic, 70 patients who had hypertension and were diagnozed with non- dipper hypertension (non-dipper hypertension group) by 24 h ambulatory blood pressure monitoring (ABPM), 70 patients with dipper hypertension patients (dipper hypertension group), and 52 normotensive individuals (control group) were enrolled in this study. Peripheral venous blood samples were collected from all the patients in order to evaluate the hematological and biochemical parameters. All the assessed parameters were compared among three groups. Results The level of UA in non-dipper hypertension group was the highest, in dipper hypertension group was higher and in contrl group was the lowerst:(393.57 ± 53.52), (280.57 ± 41.64), (267.66 ± 59.38) μmol/L, and there were significant differences (P<0.01). Multivariate Logistic regression analysis revealed that the level of UA was an independent risk factor for non-dipper circadian rhythm of blood pressure (P = 0.003, OR = 2.26, 95% CI: 1.34- 3.89). Conclusions The higher level of UA may be a risk factor for non-dipper circadian rhythm of blood pressure in hypertension patients.