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Abstract The medicinal plantCatharanthus roseusproduces numerous secondary metabolites of interest for the treatment of many diseases – most notably for the terpene indole alkaloid (TIA) vinblastine, which is used in the treatment of leukemia and Hodgkin's lymphoma. Historically, methyl jasmonate (MeJA) has been used to induce TIA production, but in the past, this has only been investigated in whole seedlings, cell culture, or hairy root culture. This study examines the effects of the phytohormones MeJA and ethylene on the induction of TIA biosynthesis and accumulation in the shoots and roots of 8‐day‐old seedlings of two varieties ofC. roseus. Using LCMS and RT‐qPCR, we demonstrate the importance of variety selection, as we observe markedly different induction patterns of important TIA precursor compounds. Additionally, both phytohormone choice and concentration have significant effects on TIA biosynthesis. Finally, our study suggests that several early‐induction pathway steps as well as pathway‐specific genes are likely to be transcriptionally regulated. Our findings highlight the need for a complete set of'omics resources in commonly usedC. roseusvarieties and the need for caution when extrapolating results from one cultivar to another.
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Characterization of the ZCTs, a subgroup of Cys2-His2 zinc finger transcription factors regulating alkaloid biosynthesis in Catharanthus roseus
Abstract Key MessageTheC. roseus ZCTsare jasmonate-responsive, can be induced by CrMYC2a, and can act as significant regulators of the terpenoid indole alkaloid pathway when highly expressed. AbstractCatharanthus roseusis the sole known producer of the anti-cancer terpenoid indole alkaloids (TIAs), vinblastine and vincristine. While the enzymatic steps of the pathway have been elucidated, an understanding of its regulation is still emerging. The present study characterizes an important subgroup of Cys2-His2 zinc finger transcription factors known asZinc fingerCatharanthusTranscription factors (ZCTs).We identified three new ZCT members (named ZCT4, ZCT5, and ZCT6) that clustered with the putative repressors of the TIA pathway, ZCT1, ZCT2, and ZCT3. We characterized the role of these six ZCTs as potential redundant regulators of the TIA pathway, and their tissue-specific and jasmonate-responsive expression. These ZCTs share high sequence conservation in their two Cys2-His2 zinc finger domains but differ in the spacer length and sequence between these zinc fingers. The transient overexpression ofZCTsin seedlings significantly repressed the promoters of the terpenoid (pLAMT) and condensation branch (pSTR1) of the TIA pathway, consistent with that previously reported for ZCT1, ZCT2, and ZCT3. In addition, ZCTs significantly repressed and indirectly activated several promoters of the vindoline pathway (not previously studied). TheZCTsdiffered in their tissue-specific expression but similarly increased with jasmonate in a dosage-dependent manner (except forZCT5). We showed significant activation of thepZCT1andpZCT3promoters by the de-repressed CrMYC2a, suggesting that the jasmonate-responsive expression of theZCTscan be mediated by CrMYC2a. In summary, theC. roseus ZCTsare jasmonate-responsive, can be induced by CrMYC2a, and can act as significant regulators of the TIA pathway when highly expressed.
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- Award ID(s):
- 2031237
- PAR ID:
- 10531886
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Plant Cell Reports
- Volume:
- 43
- Issue:
- 9
- ISSN:
- 0721-7714
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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