title: Hydrogen peroxide acts upstream of nitric oxide in the heat shock pathway in Arabidopsis seedlings.
abstract: We previously reported that nitric oxide (NO) functions as a signal in thermotolerance. To illustrate its relationship with hydrogen peroxide (H₂O₂) in the tolerance of Arabidopsis (Arabidopsis thaliana) to heat shock (HS), we investigated the effects of heat on Arabidopsis seedlings of the following types: the wild type; three NADPH oxidase-defective mutants that exhibit reduced endogenous H₂O₂ levels (atrbohB, atrbohD, and atrbohB/D); and a mutant that is resistant to inhibition by fosmidomycin (noa1, for nitric oxide-associated protein1). After HS, the NO levels in atrbohB, atrbohD, and atrbohB/D seedlings were lower than that in wild-type seedlings. Treatment of the seedlings with sodium nitroprusside or S-nitroso-N-acetylpenicillamine partially rescued their heat sensitivity, suggesting that NO is involved in H₂O₂ signaling as a downstream factor. This point was verified by phenotypic analyses and thermotolerance testing of transgenic seedlings that overexpressed Nitrate reductase2 and NOA1, respectively, in an atrbohB/D background. Electrophoretic mobility shift assays, western blotting, and real-time reverse transcription-polymerase chain reaction demonstrated that NO stimulated the DNA-binding activity of HS factors and the accumulation of HS proteins through H₂O₂. These data indicate that H₂O₂ acts upstream of NO in thermotolerance, which requires increased HS factor DNA-binding activity and HS protein accumulation.
authors: Institute of Molecular Cell Biology, School of Life Sciences, and Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang 050024, China.
authors: Lei
authors: L
authors: Wang
authors: Yunjing
authors: Y
authors: Guo
authors: Lixiu
authors: L
authors: Jia
authors: Hongye
authors: H
authors: Chu
authors: Shuo
authors: S
authors: Zhou
authors: Kunming
authors: K
authors: Chen
authors: Dan
authors: D
authors: Wu
authors: Liqun
authors: L
authors: Zhao
mesh_terms: D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D018744:DNA, Plant / Q000378:metabolism; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism*; D011485:Protein Binding; D036226:Seedlings / Q000378:metabolism*; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D009569:Nitric Oxide; D006861:Hydrogen Peroxide