Integrating Structural Bioinformatics and Functional Mechanisms of Sesquiterpene Synthases CARS and CADS in Lavandula angustifolia (Lavender)

Lavender species are economically valuable plants, widely cultivated for their essential oils (EOs), which include sesquiterpenes. The sesquiterpenes caryophyllene and cadinol are major constituents, contributing woody and balsamic notes. However, the specific enzymes catalyzing their formation in lavender have not been elucidated. This study reports the comprehensive functional and structural characterization of two pivotal sesquiterpene synthases from Lavandula angustifolia (lavender): caryophyllene synthase (CARS) and cadinol synthase (CADS). Mutation experiments were performed based on molecular docking predictions, revealing that negatively charged residues interact electrostatically with magnesium ions (Mg²⁺). Both deletion of 1–226 and 1–228 (∆1–226 and ∆1–228) display activity levels equivalent to their corresponding wild-type proteins, while deletions at positions 522–548 and 529–555 significantly enhanced enzyme activity. Additionally, the highest expression levels of CARS were in the flowers under white light for 8 h, while CADS exhibited peak expression in the leaves under white light for 12 h. These findings deepen our understanding of the regulatory mechanisms involved in sesquiterpene biosynthesis in lavender and provide insights for genetic engineering strategies aimed at enhancing EO production. Such advances could also inform the development of cosmetic, personal care, and medicinal products.