Formation of plant metabolic gene clusters within dynamic chromosomal regions

Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):16116-21. doi: 10.1073/pnas.1109273108. Epub 2011 Aug 29.


In bacteria, genes with related functions often are grouped together in operons and are cotranscribed as a single polycistronic mRNA. In eukaryotes, functionally related genes generally are scattered across the genome. Notable exceptions include gene clusters for catabolic pathways in yeast, synthesis of secondary metabolites in filamentous fungi, and the major histocompatibility complex in animals. Until quite recently it was thought that gene clusters in plants were restricted to tandem duplicates (for example, arrays of leucine-rich repeat disease-resistance genes). However, operon-like clusters of coregulated nonhomologous genes are an emerging theme in plant biology, where they may be involved in the synthesis of certain defense compounds. These clusters are unlikely to have arisen by horizontal gene transfer, and the mechanisms behind their formation are poorly understood. Previously in thale cress (Arabidopsis thaliana) we identified an operon-like gene cluster that is required for the synthesis and modification of the triterpene thalianol. Here we characterize a second operon-like triterpene cluster (the marneral cluster) from A. thaliana, compare the features of these two clusters, and investigate the evolutionary events that have led to cluster formation. We conclude that common mechanisms are likely to underlie the assembly and control of operon-like gene clusters in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases / genetics
  • Acyltransferases / metabolism
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / classification
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Chromosome Mapping
  • Chromosomes, Plant / genetics*
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism
  • Gas Chromatography-Mass Spectrometry
  • Gene Duplication
  • Gene Expression Regulation, Plant
  • Genome, Plant / genetics
  • Intramolecular Transferases / genetics
  • Intramolecular Transferases / metabolism
  • Models, Genetic
  • Molecular Structure
  • Multigene Family*
  • Mutation
  • Phylogeny
  • Plant Leaves / genetics
  • Plant Leaves / metabolism
  • Plant Roots / genetics
  • Plant Roots / metabolism
  • Plants, Genetically Modified
  • Triterpenes / analysis
  • Triterpenes / chemistry
  • Triterpenes / metabolism


  • Arabidopsis Proteins
  • Triterpenes
  • marneral
  • thalianol
  • Cytochrome P-450 Enzyme System
  • CYP71A16 protein, Arabidopsis
  • thalianol hydroxylase, Arabidopsis
  • Acyltransferases
  • At5g47980 protein, Arabidopsis
  • Intramolecular Transferases
  • marneral synthase, Arabidopsis
  • thalianol synthase, Arabidopsis
  • lanosterol synthase