title: Chromium stress response effect on signal transduction and expression of signaling genes in rice.
abstract: Hexavalent chromium [Cr(VI)] is a non-essential metal for normal plants and is toxic to plants at high concentrations. However, signaling pathways and molecular mechanisms of its action on cell function and gene expression remain elusive. In this study, we found that Cr(VI) induced endogenous reactive oxygen species (ROS) generation and Ca(2+) accumulation and activated NADPH oxidase and calcium-dependent protein kinase. We investigated global transcriptional changes in rice roots by microarray analysis. Gene expression profiling indicated activation of abscisic acid-, ethylene- and jasmonic acid-mediated signaling and inactivation of gibberellic acid-related pathways in Cr(VI) stress-treated rice roots. Genes encoding signaling components such as the protein kinases domain of unknown function 26, receptor-like cytoplasmic kinase, LRK10-like kinase type 2 and protein phosphatase 2C, as well as transcription factors WRKY and apetala2/ethylene response factor were predominant during Cr(VI) stress. Genes involved in vesicle trafficking were subjected to functional characterization. Pretreating rice roots with a vesicle trafficking inhibitor, brefeldin A, effectively reduced Cr(VI)-induced ROS production. Suppression of the vesicle trafficking gene, Exo70, by virus-induced gene silencing strategies revealed that vesicle trafficking is required for mediation of Cr(VI)-induced ROS production. Taken together, these findings shed light on the molecular mechanisms in signaling pathways and transcriptional regulation in response to Cr stress in plants.
authors.affiliation: Department of Life Sciences, National Cheng Kung University, No.1 University Road 701, Tainan, Taiwan.
authors.forename: Ngoc-Nam
authors.initials: NN
authors.lastname: Trinh
authors.forename: Tsai-Lien
authors.initials: TL
authors.lastname: Huang
authors.forename: Wen-Chang
authors.initials: WC
authors.lastname: Chi
authors.forename: Shih-Feng
authors.initials: SF
authors.lastname: Fu
authors.forename: Chi-Chien
authors.initials: CC
authors.lastname: Chen
authors.forename: Hao-Jen
authors.initials: HJ
authors.lastname: Huang
mesh_terms: D001681:Biological Assay; D020126:Brefeldin A / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002857:Chromium / Q000633:toxicity*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D063990:Gene Ontology; D020868:Gene Silencing / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D008954:Models, Biological; D019255:NADPH Oxidases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D011494:Protein Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics*; D014026:Nicotiana / Q000187:drug effects / Q000821:virology; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D020126:Brefeldin A; D002118:Calcium; D002857:Chromium; D019255:NADPH Oxidases; D010940:Plant Proteins; D011494:Protein Kinases; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C074702:chromium hexavalent ion