title: Evidence for functional interaction between brassinosteroids and cadmium response in Arabidopsis thaliana.
abstract: Plant hormones, in addition to regulating growth and development, are involved in biotic and abiotic stress responses. To investigate whether a hormone signalling pathway plays a role in the plant response to the heavy metal cadmium (Cd), gene expression data in response to eight hormone treatments were retrieved from the Genevestigator Arabidopsis thaliana database and compared with published microarray analysis performed on plants challenged with Cd. Across more than 3000 Cd-regulated genes, statistical approaches and cluster analyses highlighted that gene expression in response to Cd and brassinosteroids (BR) showed a significant similarity. Of note, over 75% of the genes showing consistent (e.g. opposite) regulation upon BR and Brz (BR biosynthesis inhibitor) exposure exhibited a BR-like response upon Cd exposure. This phenomenon was confirmed by qPCR analysis of the expression level of 10 BR-regulated genes in roots of Cd-treated wild-type (WT) plants. Although no change in BR content was observed in response to Cd in our experimental conditions, adding epibrassinolide (eBL, a synthetic brassinosteroid) to WT plants significantly enhanced Cd-induced root growth inhibition, highlighting a synergistic response between eBL and the metal. This effect was specific to this hormone treatment. On the other hand, dwarf1 seedlings, showing a reduced BR level, exhibited decreased root growth inhibition in response to Cd compared with WT, reversed by the addition of eBL. Similar results were obtained on Brz-treated WT plants. These results argue in favour of an interaction between Cd and BR signalling that modulates plant sensitivity, and opens new perspectives to understand the plant response to Cd.
authors: CEA Laboratoire de Physiologie Cellulaire Végétale, UMR5168 Commissariat à l'Energie Atomique/CNRS/Université Joseph-Fourier/INRA, Institut de Recherches en Technologies et Sciences pour le Vivant, 17 rue des Martyrs, F-38054 Grenoble cedex 9, France.
authors: Florent
authors: F
authors: Villiers
authors: Agnès
authors: A
authors: Jourdain
authors: Olivier
authors: O
authors: Bastien
authors: Nathalie
authors: N
authors: Leonhardt
authors: Shozo
authors: S
authors: Fujioka
authors: Gabrielle
authors: G
authors: Tichtincky
authors: François
authors: F
authors: Parcy
authors: Jacques
authors: J
authors: Bourguignon
authors: Véronique
authors: V
authors: Hugouvieux
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060406:Brassinosteroids / Q000378:metabolism*; D002104:Cadmium / Q000494:pharmacology*; D019295:Computational Biology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D060406:Brassinosteroids; C091574:DIM1 protein, Arabidopsis; D002104:Cadmium