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

Objective To study the changes of gastrin 17 (G17) and pepsinogen (PG) after gastric bypass surgery in gastric antrum resection, and the influences of different surgical methods on postoperative peptic ulcer. Methods Clinical data of 63 patients with gastric bypass surgery in our hospital from October 2013 to October 2015 were divided into resection of pyloric antrum group (n=33) and preserved pyloric antrum group (n=30). The values of G17, PGⅠ, PGⅡand PGⅠ/PGⅡwere detected by enzyme linked immunosorbent assay at 1 month, 6 months and 12 months after operation. The correlation between the different surgical methods and the incidence of peptic ulcer was analyzed between two groups. Results The G17 levels were significantly decreased in resection of pyloric antrum group 6 and 12 months after operation than those in preserved pyloric antrum group (P<0.05). Compared with preserved pyloric antrum group,PGⅠ and PGⅡ levels was significantly decreased 12 months after operation (P<0.05). There was no significant difference in the ratio PGⅠ/PGⅡat 1 month, 6 months and 12 months after operation between two groups (P>0.05). There was no significant difference in postoperative peptic ulcer between two groups (P>0.05). Conclusion Gastric bypass after resection of the pyloric antrum can reduce the postoperative secretion of G17, PGⅠ and PGⅡ, but which can not reduce the incidence of postoperative anastomotic ulcer.