The Phytotoxin Coronatine and Methyl Jasmonate Impact Multiple Phytohormone Pathways in Tomato

Plant J. 2005 Apr;42(2):201-17. doi: 10.1111/j.1365-313X.2005.02366.x.

Abstract

Coronatine (COR) is a phytotoxin produced by several pathovars of Pseudomonas syringae and consists of coronafacic acid (CFA), an analog of methyl jasmonic acid (MeJA), and coronamic acid (CMA), which resembles 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor to ethylene. An understanding of how COR functions, is perceived by different plant tissues, and the extent to which it mimics MeJA remain unclear. In this study, COR and related compounds were examined with respect to structure and function. The results indicate that conjugation of CFA to an amino acid is required for optimal activity in tomato, including chlorosis, changes in chloroplast structure, cell wall thickening, accumulation of proteinase inhibitors, induction of anthocyanins, and root growth inhibition. cDNA microarrays were utilized to understand the molecular processes that are regulated by MeJA, COR, CFA and CMA in tomato leaves. A comparison of COR- and MeJA-regulated transcriptomes revealed that COR regulated 35% of the MeJA-induced genes. There was significant overlap in the number of COR and CFA-regulated genes with CFA impacting the expression of 39.4% of the COR-regulated genes. Taken together, the results of biological assays, ultrastructural studies, and gene expression profiling demonstrate that: (1) the intact COR molecule impacts signaling in tomato via the jasmonic acid, ethylene, and auxin pathways; (2) CMA does not function as a structural analog of ACC; (3) COR has a broader range of functions than either CFA or CMA; and (4) COR and MeJA share similar, but not identical activities and impact multiple phytohormone pathways in tomato.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetates / chemistry
  • Acetates / pharmacology*
  • Amino Acids / chemistry
  • Amino Acids / pharmacology*
  • Bacterial Toxins / chemistry
  • Bacterial Toxins / pharmacology*
  • Cyclopentanes / chemistry
  • Cyclopentanes / pharmacology*
  • Gene Expression Regulation, Plant / drug effects
  • Indenes / chemistry
  • Indenes / pharmacology*
  • Lycopersicon esculentum / drug effects*
  • Lycopersicon esculentum / physiology
  • Molecular Structure
  • Oxylipins
  • Plant Growth Regulators / physiology*
  • Plant Leaves / drug effects
  • Plant Leaves / physiology
  • Plant Roots / drug effects
  • Plant Roots / growth & development
  • Seedlings / drug effects
  • Seedlings / growth & development
  • Signal Transduction

Substances

  • Acetates
  • Amino Acids
  • Bacterial Toxins
  • Cyclopentanes
  • Indenes
  • Oxylipins
  • Plant Growth Regulators
  • coronatine
  • methyl jasmonate