5-AzaC promotes the synthesis of patchoulol and pogostone in Pogostemon cablin by regulating DNA methylation

Abstract

Pogostemon cablin (patchouli) is an herbaceous medicinal plant with considerable economic importance in China. Patchoulol and pogostone are the principal marker compounds used in the quality assessment of patchouli oil. 5-Azacytidine (5-AzaC), a DNA methylation inhibitor, has the potential to influence secondary metabolite biosynthesis in plants. To evaluate its effects, patchouli plants were treated with different concentrations of 5-AzaC for 30 days. At a low concentration (50 μM), 5-AzaC enhanced the activity of antioxidant enzymes, whereas at a higher concentration (200 μM), it promoted the accumulation of patchoulol and pogostone. Transcriptome analysis yielded 58,144 unigenes and identified 20,586 differentially expressed genes (9535 up-regulated and 11,051 down-regulated). Of these, 731 genes were enriched in secondary metabolism pathways (188 up-regulated and 543 down-regulated), and 215 transcripts were associated with redox-related pathways (92 up-regulated and 123 down-regulated). Key genes involved in patchoulol and pogostone biosynthesis (GPPS, PTS), together with antioxidant enzyme genes (CAT, SOD, APX, ICDH, SGT), showed generally low expression. In contrast, genes encoding key methylation enzymes (MET, CMT, DRM) were down-regulated, while the DNA demethylation-related gene MBD was up-regulated. These findings suggest that 5-AzaC alters the methylation machinery of patchouli, leading to abnormal gene expression and transcriptional changes. This work provides new insights into the role of DNA methylation in regulating patchoulol and pogostone biosynthesis, and lays a foundation for further studies on the epigenetic regulation of secondary metabolism in patchouli. metabolism.