Plant Molecular Biology 51: 597-605 (2003)

Ozone-induced gene expression occurs via ethylene-dependent and -independent signalling

Grimmig B (1,5), Gonzalez-Perez M N (1,2), Leubner-Metzger G (3,6), Vögeli-Lange R (3,7), Meins F (3), Hain R (4), Penuelas J (2), Heidenreich B (1), Langebartels C (1), Ernst D (1), Sanderman H Jr (1)

(1) GSF - National Research Center for Environment and Health, Institute of Biochemical, Plant Pathology, D-85764 Neuherberg, Germany
(2) CREAF, Facultat di Ciencies, Universitat Autonoma, E-08193 Barcelona, Spain
(3) Friedrich Miescher - lnstitute for Biomedical Research, A branch of the Novartis Research Foundation, Maulbeerstr. 33, CH-4058 Basel, Switzerland
(4) Bayer AG, Landwirtschaftszentrum Monheim, Molecular Target Research and Biotechnology, D-51368 Leverkusen, Germany; Present address: (5) Bayer AG, BG Pflanzenschutz, Forschung/MW, D-51368 Leverkusen, Germany
(6) Universität Freiburg, Institut für Biologie II, Botanik, Schänzlestr. 1, D-79104 Freiburg, Germany
(7) Syngenta Crop Protection AG, Schwarzwaldallee 215, CH-4058 Basel, Switzerland

Received: 9 January 2002 / Accepted: 31 July 2002

Abstract. Recent studies suggest that ethylene is involved in signalling ozone-induced gene expression. We show here that application of ozone increased glucuronidase (GUS) expression of chimeric reporter genes regulated by the promoters of the tobacco class 1 ß-1,3-glucanases (GLB and Gln2) and the grapevine resveratrol synthase (Vstl) genes in transgenic tobacco leaves. 5'-Deletion analysis of the class I ß-1,3-glucanase promoter revealed that ozone-induced gene regulation is mainly mediated by the distal enhancer region containing the positively acting ethylene-responsive element (ERE). In addition, application of 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, blocked ozone-induced class I ß-1,3-glucanase promoter activity. Enhancer activity and ethylene-responsiveness depended on the integrity of the GCC boxes, cis-acting elements present in the ERE of the class I ß-1,3-glucanase and the basic-type pathogenesis-related PR-1 protein (PRB-1b) gene promoters. The minimal PRB-1b promoter containing only the ERE with intact GCC boxes, was sufficient to confer 10-fold ozone-inducibility to a GUS-reporter gene, while a substitution mutation in the GCC box abolished ozone responsiveness. The ERE region of the class I ß-1,3-glucanase promoter containing two intact GCC boxes confered strong ozone-inducibility to a minimal cauliflower mosaic virus (CaMV) 35S RNA promoter, wheras two single base substitution in the GCC boxes resulted in a complete loss of ozone-inducibility. Taken together, these data strongly suggest that ethylene is signalling ozone-induced expression of class I ß-1,3-glucanase genes. Promoter analysis of the stilbene synthase Vst1 gene unraveled different regions for ozone and ethylene-responsiveness. Application of 1-MCP blocked ethylene-induced Vst1 induction, but ozone induction was not affected. This shows that ozone-induced gene expression occurs via at least two different signalling mechanisms and suggests an additional ethylene independent signalling pathway for ozone-induced expression of genes involved in phytoalexin biosynthesis. 

Key words: ethylene, gene regulation, ozone, pathogenesis-related, promoter, resveratrol, stilbene

Article in PDF format (132 KB) Abstract          Fig. 1          Fig. 2          Fig. 3          Table 1
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