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The essential oil of Pelargonium graveolens (rose-scented geranium), an important aromatic plant, comprising mainly mono- and sesqui-terpenes, has applications in food and cosmetic industries. This study reports the characterization of isoprenyl disphosphate synthases (IDSs) involved in P. graveolens terpene biosynthesis. The six identified PgIDSs belonged to different classes of IDSs, comprising homomeric geranyl diphosphate synthases (GPPSs; PgGPPS1 and PgGPPS2), the large subunit of heteromeric GPPS or geranylgeranyl diphosphate synthases (GGPPSs; PgGGPPS), the small subunit of heteromeric GPPS (PgGPPS.SSUI and PgGPPS.SSUII), and farnesyl diphosphate synthases (FPPS; PgFPPS).All IDSs exhibited maximal expression in glandular trichomes (GTs), the site of aroma formation, and their expression except PgGPPS.SSUII was induced upon treatment with MeJA. Functional characterization of recombinant proteins revealed that PgGPPS1, PgGGPPS and PgFPPS were active enzymes producing GPP, GGPP/GPP, and FPP respectively, whereas both PgGPPS.SSUs and PgGPPS2 were inactive. Co-expression of PgGGPPS (that exhibited bifunctional G(G)PPS activity) with PgGPPS.SSUs in bacterial expression system showed lack of interaction between the two proteins, however, PgGGPPS interacted with a phylogenetically distant Antirrhinum majus GPPS.SSU. Further, transient expression of AmGPPS.SSU in P. graveolens leaf led to a significant increase in monoterpene levels. These findings provide insight into the types of IDSs and their role in providing precursors for different terpenoid components of P. graveolens essential oil. • Six IDSs that are highly expressed in glandular trichomes of P. graveolens were functionally characterized. • Results revealed geranium has a homomeric GPPS, a bifunctional G(G)PPS, and a FPPS involved in terpenoid precursor formation. • Enzyme kinetics indicated that both homomeric and bifunctional G(G)PPS provide precursors for monoterpene biosynthesis. [ABSTRACT FROM AUTHOR]

Vetiver is one of the valued plants in the aromatic world which has been extensively used in fragrances, aromatherapy, and medicines. The essential oils derived from vetiver root portions are mainly responsible for the organoleptic character of the plant. Vetiver essential oil is composed of diverse structural framework biosynthesized by using three isoprene units or sesquitepene leading to a number of bicyclic, tricyclic and tetracylic structures. Sequiterpenoids contribute major proportion to vetiver (Chrysopogon zizanioides) roots. However, the terpene synthases and their role in sesquiterpene biosynthesis in plant have not yet been studied. On the basis of volatile composition, two distinct stable vetiver genotypes viz., 'CIM-Vridhi' and 'CIMAP-Khusinolika' have been identified in 'CSIR-CIMAP' in recent years. Such a unique chemical difference is attributed to the array of structural diversity in sesquiterpenes and their derivatives. The root transcriptome of the two contrasting genotypes 'CIM-Vridhi' and 'CIMAP-Khusinolika' was carried out and three full length terpene synthase (TPS) genes were analyzed. These synthase genes, CZTPS1 , CZTPS2 , and CZTPS3 produce multiple sesquiterpenoids and were functionally characterized. In addition, the gene expression studies leading to metabolite biosynthesis in these genotypes were further confirmed by compound isolation and NMR based structural characterization of compounds from each genotypes. A bicyclic cadinane called khusinol identified as unique identifier in 'CIMAP-Khusinolika' while khusimol, a tricyclic zizaene dominates the 'CIM-Vridhi' oil composition. In conclusion, characterization of unique markers in each genotypes has been well supported by their transcriptomic data. Thus, present study can be utilized to investigate the vetiver terpenoid metabolism and its structure–odor correlations for the production of more potent odor threshold oriented chemicals from this plant. [Display omitted] • Chemically distinct vetiver types 'CIM-Vridhi' and 'CIMAP-Khusinolika' were studied. • Role of terpene synthases in sesquiterpene biosynthesis was investigated. • Terpene synthase genes CZTPS1, CZTPS2, and CZTPS3 produce multiple sesquiterpenoids. • nor -zizaene, zizaene and prezizaane were major odor contributors in vetiver oils. • Structural characterization of sequiterpenoids was carried out using NMR experiments. [ABSTRACT FROM AUTHOR]

Curcuma amada Roxb. is a valuable medicinal herb with food, economic, pharmaceutical, and industrial value. This plant is commonly propagated through rhizome which is season dependent and slow process. Moreover, rhizomes are easily infected by different soil-borne pathogen, which deteriorates the quality and quantity of production. Hence, this study was carried out to develop one step plant regeneration protocol using rhizomatic bud on meta-Topolin (mT) supplemented medium. About 600 plants were produced on Murashige and Skoog (1962) (MS) medium added with 3.0 mg/L mT after twelve weeks of culture. Well rooted plants were successfully hardened (95%) and subsequently all the plants were established in the field. Quantitative phytochemical analysis and assessment of chemical composition of essential oil by Gas Chromatography - Mass Spectroscopy (GC-MS) confirmed the biochemical fidelity of the field-established tissue culture plants. Robust therapeutic activities such as antioxidant, anticancer, and antimicrobial activities were found in the rhizome extract and essential oil of the field-established tissue culture plants. It was concluded that tissue cultured plants are at par with the mother plant in terms of phytochemicals composition and therapeutic activity. Thus, this protocol could be useful for the production of a large number of plants aiming for its conservation, propagation as well as sustainable utilization in food, beverage, and pharmaceutical industries. • Micropropagation protocol was developed for C. amada using rhizomatic explant. • Phytochemical of rhizome and chemical composition of rhizome essential oil was analyzed. • Therapeutic activities i.e., antioxidant, anticancer, and antimicrobial activity were studied. • Filed-established tissue culture plants were found stable based on phytochemical and pharmacological studies. • This protocol could be useful for large scale propagation as well as sustainable utilization. [ABSTRACT FROM AUTHOR]