title: The glucosinolate breakdown product indole-3-carbinol acts as an auxin antagonist in roots of Arabidopsis thaliana.
abstract: The glucosinolate breakdown product indole-3-carbinol functions in cruciferous vegetables as a protective agent against foraging insects. While the toxic and deterrent effects of glucosinolate breakdown on herbivores and pathogens have been studied extensively, the secondary responses that are induced in the plant by indole-3-carbinol remain relatively uninvestigated. Here we examined the hypothesis that indole-3-carbinol plays a role in influencing plant growth and development by manipulating auxin signaling. We show that indole-3-carbinol rapidly and reversibly inhibits root elongation in a dose-dependent manner, and that this inhibition is accompanied by a loss of auxin activity in the root meristem. A direct interaction between indole-3-carbinol and the auxin perception machinery was suggested, as application of indole-3-carbinol rescues auxin-induced root phenotypes. In vitro and yeast-based protein interaction studies showed that indole-3-carbinol perturbs the auxin-dependent interaction of Transport Inhibitor Response (TIR1) with auxin/3-indoleacetic acid (Aux/IAAs) proteins, further supporting the possibility that indole-3-carbinol acts as an auxin antagonist. The results indicate that chemicals whose production is induced by herbivory, such as indole-3-carbinol, function not only to repel herbivores, but also as signaling molecules that directly compete with auxin to fine tune plant growth and development.
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Ella
authors.initials: E
authors.lastname: Katz
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Sophia
authors.initials: S
authors.lastname: Nisani
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Brijesh S
authors.initials: BS
authors.lastname: Yadav
authors.affiliation: Boyce Thompson Institute, Ithaca, NY, 14853, USA.
authors.forename: Melkamu G
authors.initials: MG
authors.lastname: Woldemariam
authors.affiliation: Cell Research and Immunology, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Ben
authors.initials: B
authors.lastname: Shai
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Obolski
authors.affiliation: Cell Research and Immunology, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Ehrlich
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Eilon
authors.initials: E
authors.lastname: Shani
authors.affiliation: Boyce Thompson Institute, Ithaca, NY, 14853, USA.
authors.forename: Georg
authors.initials: G
authors.lastname: Jander
authors.affiliation: Molecular Biology and Ecology of Plants, Tel Aviv University, Ramat Aviv, 69978, Israel.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Chamovitz
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005961:Glucosinolates / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors; D007211:Indoles / Q000378:metabolism* / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D005961:Glucosinolates; D007210:Indoleacetic Acids; D007211:Indoles; C030737:indoleacetic acid; C016517:indole-3-carbinol
keywords: Arabidopsis thaliana; auxin; glucosinolate; herbivory; indole-3-carbinol