Identification of Iridoid Glucoside Transporters in Catharanthus roseus

Research output: Contribution to journalArticle

Abstract

Monoterpenoid indole alkaloids (MIAs) are plant defense compounds and high-value pharmaceuticals. Biosynthesis of the universal MIA precursor, secologanin, is organized between internal phloem-associated parenchyma (IPAP) and epidermis cells. Transporters for intercellular transport of proposed mobile pathway intermediates have remained elusive. Screening of an Arabidopsis thaliana transporter library expressed in Xenopus oocytes identified AtNPF2.9 as a putative iridoid glucoside importer. Eight orthologs were identified in Catharanthus roseus, of which three, CrNPF2.4, CrNPF2.5 and CrNPF2.6, were capable of transporting the iridoid glucosides 7-deoxyloganic acid, loganic acid, loganin and secologanin into oocytes. Based on enzyme expression data and transporter specificity, we propose that several enzymes of the biosynthetic pathway are present in both IPAP and epidermis cells, and that the three transporters are responsible for transporting not only loganic acid, as previously proposed, but multiple intermediates. Identification of the iridoid glucoside-transporting CrNPFs is an important step toward understanding the complex orchestration of the seco-iridioid pathway.

Details

Authors
  • Lars Bo Larsen
  • Victoria L Fuller
  • Jacob Pollier
  • Alex Van Moerkercke
  • Fabian Schweizer
  • Richard J. Payne
  • Maite Colinas
  • Sarah E O'Connor
  • Alain Goossens
  • Barbara A Halkier
External organisations
  • Flanders Interuniversity Institute for Biotechnology
  • University of Copenhagen
  • Ghent University
  • John Innes Centre
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biochemistry and Molecular Biology
Original languageEnglish
Pages (from-to)1507-1518
Number of pages12
JournalPlant and Cell Physiology
Volume58
Issue number9
Publication statusPublished - 2017 Sep 1
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes