Terpene profiling, transcriptome analysis and characterization of cis-β-terpineol synthase from Ocimum
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Ocimum species produces a varied mix of different metabolites that imparts immense medicinal properties. To explore this chemo-diversity, we initially carried out metabolite profiling of different tissues of five Ocimum species and identified the major terpenes. This analysis broadly classified these five Ocimum species into two distinct chemotypes namely, phenylpropanoid-rich and terpene-rich. In particular, β-caryophyllene, myrcene, limonene, camphor, borneol and selinene were major terpenes present in these Ocimum species. Subsequently, transcriptomic analysis of pooled RNA samples from different tissues of Ocimum gratissimum, O. tenuiflorum and O. kilimandscharicum identified 38 unique transcripts of terpene synthase (TPS) gene family. Full-length gene cloning, followed by sequencing and phylogenetic analysis of three TPS transcripts were carried out along with their expression in various tissues. Terpenoid metabolite and expression profiling of candidate TPS genes in various tissues of Ocimum species revealed spatial variances. Further, putative TPS contig 19414 (TPS1) was selected to corroborate its role in terpene biosynthesis. Agrobacterium-mediated transient over-expression assay of TPS1 in the leaves of O. kilimandscharicum and subsequent metabolic and gene expression analyses indicated it as a cis-β-terpineol synthase. Overall, present study provided deeper understanding of terpene diversity in Ocimum species and might help in the enhancement of their terpene content through advanced biotechnological approaches.
KeywordsAgro-infiltration assay Metabolite profiling Ocimum Terpenes Terpene synthase Transcriptome
AA and SGL acknowledge Council of Scientific and Industrial Research (CSIR), New Delhi for SRF while SB acknowledges University Grants Commission, New Delhi, India for Kothari fellowship. The work was funded by CSIR-NCL-IGIB Joint Research program under XII Five Year Plan (BSC0124).
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Conflict of interest
The authors declare that there are no conflicts of interest.
- Anand A, Jayaramaiah RH, Beedkar SD, Singh PA, Joshi RS, Mulani FA, Dholakia BB, Punekar SA, Gade WN, Thulasiram HV, Giri AP (2016) Comparative functional characterization of eugenol synthase from four different Ocimum species: implications on eugenol accumulation. Biochim Biophys Acta Proteins Proteomics 1864:1539–1547CrossRefGoogle Scholar
- Davis EM, Croteau R (2000) Cyclization enzymes in the biosynthesis of monoterpenes, sesquiterpenes and diterpenes, vol 209. Springer, New York, pp 53–95Google Scholar
- Ramesha HJ, Anand A, Beedkar SD, Dholakia BB, Punekar SA, Kalunke RM, Gade WN, Thulasiram HV, Giri AP (2016) Functional characterization and transient expression manipulation of a new sesquiterpene synthase involved in β-caryophyllene accumulation in Ocimum. Biochem Biophys Res Commun 473:265–271CrossRefGoogle Scholar
- Sprenger GA, Schorken U, Wiegert T, Grolle S, de Graaf AA, Taylor SV, Begley TP, Bringer-Meyer S, Sahm H (1997) Identification of a thiamin-dependent synthase in Escherichia coli required for the formation of the 1-deoxy-D-xylulose 5-phosphate precursor to isoprenoids, thiamin, and pyridoxol. Proc Natl Acad Sci USA 94:12857–12862CrossRefGoogle Scholar