The indolic compound hypaphorine produced by ectomycorrhizal fungus interferes with auxin action and evokes early responses in nonhost Arabidopsis thaliana.
Signals leading to mycorrhizal differentiation are largely unknown. We have studied the sensitivity of the root system from plant model Arabidopsis thaliana to hypaphorine, the major indolic compound isolated from the basidiomycetous fungus Pisolithus tinctorius. This fungi establishes ectomycorrhizas with Eucalyptus globulus. Hypaphorine controls root hair elongation and counteracts the activity of indole-3-acetic acid on root elongation on A. thaliana, as previously reported for the host plant. In addition, we show that hypaphorine counteracts the rapid upregulation by indole-3-acetic acid and 1-naphthalenic-acetic acid of the primary auxin-responsive gene IAA1 and induces a rapid, transient membrane depolarization in root hairs and suspension cells, due to the modulation of anion and K+ currents. These early responses indicate that components necessary for symbiosis-related differentiation events are present in the nonhost plant A. thaliana and provide tools for the dissection of the hypaphorine-auxin interaction.
Reboutier
David
D
Laboratoire d'Electrophysiologie des Membranes EA 3514, Université Denis Diderot-Paris 7, France.
Bianchi
Michele
M
Brault
Mathias
M
Roux
Camille
C
Dauphin
Aurélien
A
Rona
Jean-Pierre
JP
Legué
Valérie
V
Lapeyrie
Frédéric
F
Bouteau
François
F
D017360:Arabidopsis / Q000187:drug effects* / Q000254:growth & development / Q000382:microbiology; D029681:Arabidopsis Proteins; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000187:drug effects; D004336:Drug Antagonism; D005982:Glutathione Transferase / Q000187:drug effects / Q000235:genetics; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007211:Indoles / Q000378:metabolism / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D038821:Mycorrhizae / Q000254:growth & development / Q000378:metabolism*; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D009687:Nuclear Proteins / Q000187:drug effects; D010940:Plant Proteins; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C491592:IAA1 protein, Arabidopsis; C109031:IAA1 protein, plant; D007210:Indoleacetic Acids; D007211:Indoles; D009280:Naphthaleneacetic Acids; D009687:Nuclear Proteins; D010940:Plant Proteins; C034182:1-naphthaleneacetic acid; C030737:indoleacetic acid; D005982:Glutathione Transferase; C001529:lenticin