Expression Analysis and Functional Validation of DcTPSb1 in Terpene Synthesis of <i>Dendrobium chrysotoxum</i>
Terpenes are critical components of the floral fragrance component in <i>Dendrobium chrysotoxum</i>, synthesized by terpene synthase (TPS). Analysis of the <i>D. chrysotoxum</i> genome and transcriptional data revealed that the gene <i>DcTPSb1</i> was significantl...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Current Issues in Molecular Biology |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1467-3045/47/1/25 |
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| Summary: | Terpenes are critical components of the floral fragrance component in <i>Dendrobium chrysotoxum</i>, synthesized by terpene synthase (TPS). Analysis of the <i>D. chrysotoxum</i> genome and transcriptional data revealed that the gene <i>DcTPSb1</i> was significantly up-regulated during flowering periods, showing a strong correlation with the accumulation of aromatic monoterpenes in the floral components of <i>Dendrobium chrysotoxum</i>. Consequently, the <i>DcTPSb1</i> gene was selected for further analysis. <i>DcTPSb1</i> exhibited elevated expression levels in flowers among four organs (roots, stems, leaves, flowers) of <i>D. chrysotoxum</i>, with the highest expression observed during the blooming phase, which aligned with the accumulation of volatile terpenes during flowering. DcTPSb1, located in the chloroplasts, was identified as a member of the TPS-b subfamily associated with monoterpenes synthesis, showing close phylogenetic relationships with homologous proteins in related plant species. An analysis of the promoter region of <i>DcTPSb1</i> indicated that it may be regulated by methyl jasmonate (MeJA) responsiveness. Functionally, DcTPSb1 was shown to catalyze the conversion of geranyl diphosphate (GPP) to linalool, ocimene, and (-)-α-pinitol in vitro. Overexpression of <i>DcTPSb1</i> in tobacco resulted in a significant increase in terpenoid release during the blooming stage; however, the up-regulated substances did not include their catalytic products. The classification of DcTPSb1 as a terpene synthase capable of producing multiple products provides valuable insights into the complex biosynthesis of terpenes in orchids. These findings enhance our understanding of the functional diversity of <i>DcTPSb1</i> and the processes involved in terpene biosynthesis in orchids. |
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| ISSN: | 1467-3037 1467-3045 |