Stimulation of carotenoid metabolism in arbuscular mycorrhizal roots

Planta. 2002 Nov;216(1):148-54. doi: 10.1007/s00425-002-0917-z. Epub 2002 Nov 12.

Abstract

Development of arbuscular mycorrhizal roots is correlated with accumulation of various isoprenoids, i.e. acyclic C(14) polyene 'mycorradicin' and C(13) cyclohexenone derivatives. We present data indicating a strong stimulation of carotenoid metabolism in such roots. Carotenoid profiling revealed mycorrhiza-specific accumulation of zeta-carotene in Zea mays and Medicago truncatula. Precursor accumulation after inhibition of phytoene desaturase (Pds) activity by norflurazon indicated an increased phytoene biosynthetic capacity in mycorrhizal roots of all species analyzed. Nicotiana tabacum plants transformed with a PDS promoter- GUS construct showed a cell-specific induction of PDS promoter activity in root cells containing arbuscules. Mycorradicin biosynthesis and, partially, mycorrhization were impaired in maize mutants deficient in carotenoid biosynthesis. These data indicate that (1) mycorradicin is probably synthesized via a C(40) precursor carotenoid, (2) carotenoid biosynthesis is induced in mycorrhizal roots, (3) induction occurs, at least partially, at the transcriptional level, and (4) that this may play a functional role during mycorrhization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carotenoids / metabolism*
  • Dicarboxylic Acids / metabolism
  • Gene Expression Regulation, Enzymologic
  • Glucuronidase / genetics
  • Glucuronidase / metabolism
  • Medicago / genetics
  • Medicago / metabolism
  • Medicago / microbiology
  • Mutation
  • Mycorrhizae / growth & development*
  • Oxidoreductases / antagonists & inhibitors
  • Oxidoreductases / genetics
  • Oxidoreductases / metabolism
  • Plant Roots / genetics
  • Plant Roots / metabolism*
  • Plant Roots / microbiology
  • Polyenes / metabolism
  • Pyridazines / pharmacology
  • Tobacco / genetics
  • Tobacco / metabolism
  • Tobacco / microbiology
  • Zea mays / genetics
  • Zea mays / metabolism
  • Zea mays / microbiology

Substances

  • Dicarboxylic Acids
  • Polyenes
  • Pyridazines
  • mycorradicin
  • Carotenoids
  • (all-E) phytoene
  • Oxidoreductases
  • phytoene dehydrogenase
  • Glucuronidase
  • norflurazone