title: Suppression of Fe deficiency gene expression by jasmonate.
abstract: Fe deficiency genes are regulated in response to external supply of Fe as well as internal plant signals. Internal plant signals include plant hormones and systemic signals which coordinate shoot physiological requirements for Fe with local availability of Fe in roots. Induction of IRT1 and FRO2 gene expression can be used to monitor the Fe deficiency status of plant roots. Here, we investigated the role of jasmonate in the regulation of Fe deficiency responses and in the split root system. We found that jasmonate suppressed expression levels of IRT1 and FRO2 but not their inducibility in response to Fe deficiency. Analysis of the jasmonate-resistant mutant jar1-1 and pharmacological application of the lipoxygenase inhibitor ibuprofene supported an inhibitory effect of this plant hormone. Inhibition of IRT1 and FRO2 gene expression by jasmonate did not require the functional regulator FIT. By performing split root analyses we found that systemic down-regulation of Fe deficiency responses by Fe sufficiency of the shoot was not compromised by ibuprofene and in the jasmonate-insensitive mutant coi1-1. Therefore, we conclude that jasmonate acts as an inhibitor in fine-tuning Fe deficiency responses but that it is not involved in the systemic down-regulation of Fe deficiency responses in the root.
authors.affiliation: Dept. Biosciences-Plant Biology, Saarland University, Campus A2.4, D-66123 Saarbrücken, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Maurer
authors.forename: Sabine
authors.initials: S
authors.lastname: Müller
authors.forename: Petra
authors.initials: P
authors.lastname: Bauer
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D038181:FMN Reductase / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D007501:Iron / Q000378:metabolism; D008084:Lipoxygenase / Q000187:drug effects / Q000378:metabolism; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D054883:Oxylipins / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D027682:Cation Transport Proteins; D003517:Cyclopentanes; D038181:FMN Reductase; D007501:Iron; D008084:Lipoxygenase; D016859:Lipoxygenase Inhibitors; D054883:Oxylipins; D010937:Plant Growth Regulators; C501411:FIT1 protein, Arabidopsis; C099651:IRT1 protein, Arabidopsis; C011006:jasmonic acid; C023903:ferric citrate iron reductase