PcCD2 , PcGL2 , and PcML1 Promote Patchouli Essential Oil Production by Regulating Glandular Trichome Development in Pogostemon cablin

Patchouli essential oil, derived from volatile compounds produced by Pogostemon cablin, has wide-ranging medicinal and industrial applications. It is primarily synthesized, secreted, and stored in the epidermal trichomes of the plant. However, the molecular mechanisms that regulate trichome development remain poorly understood. Through transcriptomic and bioinformatics analyses, we identified three novel candidate genes, designated PcCD2, PcGL2, and PcML1, that play a critical role in regulating trichome development in P. cablin. Using virus-induced gene silencing (VIGS) to silence these target genes, we observed a significant reduction in trichome density, which was accompanied by a marked decrease in the major sesquiterpene components of patchouli essential oil, including patchouli alcohol and pogostone. In contrast, overexpression of these genes resulted in a substantial increase in the levels of patchouli alcohol and pogostone. These findings indicate that PcCD2, PcGL2, and PcML1 positively regulate both trichome development and sesquiterpene biosynthesis in the glandular trichomes of P. cablin. Our results elucidate the molecular mechanisms underlying trichome development in P. cablin, which may enhance its resistance to insect pests. Importantly, this study reveals a crucial link between trichome formation and sesquiterpenoid biosynthesis in P. cablin, providing novel molecular targets for precision breeding of medicinal plants.