A differentially regulated AP2/ERF transcription factor gene cluster acts downstream of a MAP kinase cascade to modulate terpenoid indole alkaloid biosynthesis in Catharanthus roseus

Priyanka Paul, Sanjay K. Singh, Barunava Patra, Xueyi Sui, Sitakanta Pattanaik, Ling Yuan

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

Catharanthus roseus produces bioactive terpenoid indole alkaloids (TIAs), including the chemotherapeutics, vincristine and vinblastine. Transcriptional regulation of TIA biosynthesis is not fully understood. The jasmonic acid (JA)-responsive AP2/ERF transcription factor (TF), ORCA3, and its regulator, CrMYC2, play key roles in TIA biosynthesis. ORCA3 forms a physical cluster with two uncharacterized AP2/ERFs, ORCA4 and 5. Here, we report that (1) the ORCA gene cluster is differentially regulated; (2) ORCA4, while overlapping functionally with ORCA3, modulates an additional set of TIA genes. Unlike ORCA3, ORCA4 overexpression resulted in dramatic increase of TIA accumulation in C. roseus hairy roots. In addition, CrMYC2 is capable of activating ORCA3 and co-regulating TIA pathway genes concomitantly with ORCA3. The ORCA gene cluster and CrMYC2 act downstream of a MAP kinase cascade that includes a previously uncharacterized MAP kinase kinase, CrMAPKK1. Overexpression of CrMAPKK1 in C. roseus hairy roots upregulated TIA pathways genes and increased TIA accumulation. This work provides detailed characterization of a TF gene cluster and advances our understanding of the transcriptional and post-translational regulatory mechanisms that govern TIA biosynthesis in C. roseus.

Original languageEnglish
Pages (from-to)1107-1123
Number of pages17
JournalNew Phytologist
Volume213
Issue number3
DOIs
StatePublished - Feb 1 2017

Bibliographical note

Funding Information:
We thank John May (Department of Civil Engineering and Environmental Research Training Laboratories, University of Kentucky, USA) for assistance in LC-MS/MS analysis and Kathy Shen for critical reading of the manuscript. This work is supported partially by the Harold R. Burton Endowed Professorship to L.Y. and by the National Science Foundation under Cooperative Agreement no. 1355438, to L.Y.

Publisher Copyright:
© 2016 The Authors. New Phytologist © 2016 New Phytologist Trust

Keywords

  • AP2/ERF gene cluster
  • Catharanthus roseus (Madagascar periwinkle)
  • MAP kinase
  • phosphorylation
  • terpenoid indole alkaloids (TIAs)
  • transcriptional regulation

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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