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Article
The ORCA2 transcription factor plays a key role in regulation of the terpenoid indole alkaloid pathway
BMC Plant Biology
  • Chun Yao Li, University of Minnesota - Twin Cities
  • Alex L. Leopold, University of Minnesota - Twin Cities
  • Guy W. Sander, University of Minnesota - Duluth
  • Jacqueline V. Shanks, Iowa State University
  • Le Zhao, Iowa State University
  • Susan I Gibson, University of Minnesota - Twin Cities
Document Type
Article
Publication Version
Published Version
Publication Date
1-1-2013
DOI
10.1186/1471-2229-13-155
Abstract

Background: The terpenoid indole alkaloid (TIA) pathway leads to the production of pharmaceutically important drugs, such as the anticancer compounds vinblastine and vincristine. Unfortunately, these drugs are produced in trace amounts, causing them to be very costly. To increase production of these drugs, an improved understanding of the TIA regulatory pathway is needed. Towards this end, transgenic Catharanthus roseus hairy roots that overexpress the ORCA2 TIA transcriptional activator were generated and characterized.Results: Transcriptional profiling experiments revealed that overexpression of ORCA2 results in altered expression of key genes from the indole and terpenoid pathways, which produce precursors for the TIA pathway, and from the TIA pathway itself. In addition, metabolite-profiling experiments revealed that overexpression of ORCA2 significantly affects the levels of several TIA metabolites. ORCA2 overexpression also causes significant increases in transcript levels of several TIA regulators, including TIA transcriptional repressors.Conclusions: Results presented here indicate that ORCA2 plays a critical role in regulation of TIA metabolism. ORCA2 regulates expression of key genes from both feeder pathways, as well as the genes (STR and SGD) encoding the enzymes that catalyze the first two steps in TIA biosynthesis. ORCA2 may play an especially important role in regulation of the downstream branches of the TIA pathway, as it regulates four out of five genes characterized from this part of the pathway. Regulation of TIA transcriptional repressors by ORCA2 may provide a mechanism whereby increases in TIA metabolite levels in response to external stimuli are transient and limited in magnitude.

Comments

This is an article from BMC Plant Biology 13 (2013): article number 155, doi: 10.1186/1471-2229-13-155. Posted with permission.

Rights
© 2013 Li et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright Owner
Li et al
Language
en
Date Available
2015-03-18
File Format
application/pdf
Citation Information
Li et al.: The ORCA2 transcription factor plays a key role in regulation of the terpenoid indole alkaloid pathway. BMC Plant Biology 2013 13:155.