title: Arabidopsis CYP82C4 expression is dependent on Fe availability and circadian rhythm, and correlates with genes involved in the early Fe deficiency response.
abstract: Under conditions of reduced iron availability, most frequent in calcareous soils, plants induce the "Fe Deficiency Response" to improve root Fe uptake. The transcription factor FIT is essential for such a response in strategy I plants, such as Arabidopsis thaliana. From microarray analysis of Arabidopsis roots, it is known that three different cytochrome P450 genes, CYP82C4, CYP82C3 and CYP71B5 are up-regulated under Fe deficiency through a FIT-dependent pathway. We show that, out of these three P450 genes, only CYP82C4 strongly correlates with genes involved in metal uptake/transport. The CYP82C4 promoter, unlike those of CYP82C3 and CYP71B5, contains several IDE1-like sequences (iron deficiency-responsive element) as well as an RY element. While confirming that the CYP82C4 transcript accumulates in Fe-deficient Arabidopsis seedlings, with circadian fluctuations in a light-dependent way, we also demonstrate that such accumulation is suppressed under Fe excess. Full suppression of CYP82C4 expression, as observed in the atc82c4-1 KO mutant, is associated with longer roots at the seedling stage. We propose that CYP82C4 is involved in the early Fe deficiency response, possibly through an IDE1-like mediated pathway.
authors.affiliation: Sezione di Fisiologia e Biochimica delle Piante, Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy. irene.murgia@unimi.it
authors.forename: Irene
authors.initials: I
authors.lastname: Murgia
authors.forename: Delia
authors.initials: D
authors.lastname: Tarantino
authors.forename: Carlo
authors.initials: C
authors.lastname: Soave
authors.forename: Piero
authors.initials: P
authors.lastname: Morandini
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007501:Iron / Q000378:metabolism; D000090463:Iron Deficiencies; D016254:Mutagenesis, Insertional; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D036226:Seedlings / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003577:Cytochrome P-450 Enzyme System; D007501:Iron