Protein phosphatase NtPP2C2b and MAP kinase NtMPK4 act in concert to modulate nicotine biosynthesis

Xiaoyu Liu, Sanjay Kumar Singh, Barunava Patra, Yongliang Liu, Bingwu Wang, Jinsheng Wang, Sitakanta Pattanaik, Ling Yuan

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Protein phosphatases (PPs) and protein kinases (PKs) regulate numerous developmental, defense, and phytohormone signaling processes in plants. However, the underlying regulatory mechanism governing biosynthesis of specialized metabolites, such as alkaloids, by the combined effects of PPs and PKs, is insufficiently understood. Here, we report the characterization of a group B protein phosphatase type 2C, NtPP2C2b, that likely acts upstream of the NICOTINE2 locus APETALA 2/Ethylene Response Factors (AP2/ERFs), to regulate nicotine biosynthesis in tobacco. Similar to the nicotine pathway genes, NtPP2C2b is highly expressed in roots and induced by jasmonic acid (JA). Overexpression of NtPP2C2b in transgenic hairy roots or stable transgenic tobacco plants repressed nicotine pathway gene expression and reduced nicotine accumulation. Additionally, transient overexpression of NtPP2C2b, together with the NtERF221, repressed transactivation of the quinolinate phosphoribosyltransferase promoter in tobacco cells. We further demonstrate that the JA-responsive tobacco mitogen-activated protein kinase (MAPK) 4 interacts with NtPP2C2b in yeast and plant cells. Conditional overexpression of NtMPK4 in tobacco hairy roots up-regulated nicotine pathway gene expression and increased nicotine accumulation. Our findings suggest that a previously uncharacterized PP-PK module acts to modulate alkaloid biosynthesis, highlighting the importance of post-translational control in the biosynthesis of specialized plant metabolites.

Original languageEnglish
Pages (from-to)1661-1676
Number of pages16
JournalJournal of Experimental Botany
Volume72
Issue number5
DOIs
StatePublished - Feb 27 2021

Bibliographical note

Publisher Copyright:
© 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Keywords

  • Alkaloid biosynthesis
  • MAP kinase
  • gene regulation
  • hairy roots
  • nicotine
  • protein phosphatase 2C
  • secondary metabolism
  • tobacco

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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