Heat stress-induced H2O2 is required for effective expression of heat shock genes in Arabidopsis |
| |
Authors: | Roman A Volkov Irina I Panchuk Phillip M Mullineaux Friedrich Schöffl |
| |
Institution: | 1. Zentrum für Molekularbiologie der Pflanzen – Allgemeine Genetik, Universit?t Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany 3. Department of Molecular Genetics and Biotechnology, University of Chernivtsy, Kotsubinsky str. 2, 58012, Ukraine 2. Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
|
| |
Abstract: | The mechanisms of sensing and signalling of heat and oxidative stresses are not well understood. The central question of this
paper is whether in plant cells oxidative stress, in particular H2O2, is required for heat stress- and heat shock factor (HSF)-dependent expression of genes. Heat stress increases intracellular
accumulation of H2O2 in Arabidopsis cell culture. The accumulation was greatly diminished using ascorbate as a scavenger or respectively diphenyleneiodonium
chloride (DPI) as an inhibitor of reactive oxygen species production. The mRNA of heat shock protein (HSP) genes, exemplified
by Hsp17.6, Hsp18.2, and the two cytosolic ascorbate peroxidase genes Apx1, Apx2, reached similar levels by moderate heat stress (37°C) or by treatment with H2O2, butylperoxide and diamide at room temperature. The heat-induced expression levels were significantly reduced in the presence
of ascorbate or DPI indicating that H2O2 is an essential component in the heat stress signalling pathway. Rapid (15 min) formation of heat shock promoter element
(HSE) protein-binding complex of high molecular weight in extracts of heat-stressed or H2O2-treated cells and the inability to form this complex after ascorbate treatment suggests that oxidative stress affects gene
expression via HSF activation and conversely, that H2O2 is involved in HSF activation during the early phase of heat stress. The heat stress induction of a high mobility HSE-binding
complex, characteristic for later phase of heat shock response, was blocked by ascorbate and DPI. H2O2 was unable to induce this complex suggesting that H2O2 is involved only in the early stages of HSF activation. Significant induction of the genes tested after diamid treatment
and moderate expression of the sHSP genes in the presence of 50 mM ascorbate at 37°C occurred without activation of HSF, indicating
that other mechanisms may be involved in stress signalling.
Electronic Supplementary Material Supplementary material is available for this article at http//dx.doi.org/10.1007/s11103-006-0045-4
Roman A. Volkov and Irina I. Panchuk contributed equally |
| |
Keywords: | Ascorbate peroxidase DPI Heat shock factor Heat shock protein Hydrogen peroxide Oxidative stress |
本文献已被 PubMed SpringerLink 等数据库收录! |
|