Identification and functional characterization of a γ-terpinene synthase in Nigella sativa L (black cumin). (October 2022)

• Record Type: Journal Article
• Authors: Elyasi, Rizan; Majdi, Mohammad; Krause, Sandra T.; Kücükay, Nagihan; Azizi, Abdolbaset; Degenhardt, Jörg
• Is Part Of: Phytochemistry. Volume 202(2022)
• Publication Date: 2022-10
• Subjects: Nigella sativa -- Ranunculaceae -- Essential oil -- Terpene synthase -- γ-Terpinene; IDP isopentenyl diphosphate -- DMADP dimethylallyl diphosphate -- GDP geranyl diphosphate -- MTS monoterpene synthase -- MEP methyl erythritol phosphate -- RACE rapid amplification of cDNA ends -- GC-MS Gas chromatography-mass spectrometry; Botanical chemistry -- Periodicals; Biochemistry -- Periodicals; Botany -- Periodicals; Chimie végétale -- Périodiques; 572.2
• DOI: 10.1016/j.phytochem.2022.113290
• Languages: English
• ISSNs: 0031-9422

Abstract

Abstract: Nigella sativa (Black cumin) has many applications in food and pharmaceutical industries. Thymoquinone has been considered as a main effective compound in N. sativa seeds and attracted researchers' attention mainly due to its medicinal potential. In this study, the essential oil components of leaves, flowers and seed developmental stages including half black seeds, soft black seeds and hard black seeds were analyzed in N. sativa . Whereas no terpenes were detected in flowers and leaves, seeds showed an essential oil composition that increased in its thymoquinone content during seed maturation. To study the proposed first step of thymoquinone biosynthesis, the formation of γ-terpinene from geranyl diphosphate (GDP), we identified and functionally characterized a γ-terpinene synthase ( Ns TPS1) in N. sativa . This monoterpene synthase was identified in RNA sequence data derived from seeds. After heterologous expression in Escherichia coli, partially purified Ns TPS1 converted GDP to γ-terpinene. Ns TPS1 is the first functionally characterized terpene synthase from N. sativa and displays a higher similarity to other terpene synthases from Ranunculaceae than known γ-terpinene synthases from more distant plant species. Characterization of Ns TPS1 elucidates the first dedicated step in the biosynthesis of thymoquinone in N. sativa and paves the way towards metabolic engineering for high-level thymoquinone production. Graphical abstract: Image 1 Highlights: Content and composition of essential oils are spatially and developmentally regulated. Thymoquinone is mostly accumulated in seeds of N. sativa. A gene encoding gamma terpinene synthase ( Ns TPS1) was cloned and functionally characterized in N. sativa. ► Ns TPS1 does not show high similarity with its orthologs from other plant species.