Induction of defence gene expression by oligogalacturonic acid requires increases in both cytosolic calcium and hydrogen

Abstract： Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression. 作 者： Xiang Yang HU    Steven J NEILL    Wei Ming CAI    Zhang Cheng TANG   作者單位： Xiang Yang HU,Wei Ming CAI,Zhang Cheng TANG(Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China)

Steven J NEILL(Centre for Research in Plant Science, University of the West of England, Bristol, Coldharbour Lane, Bristol BS16 1QY, UK) 

期 刊： 細胞研究（英文版）  ISTICSCI   Journal： CELL RESEARCH  年，卷(期)： 2004, 14(3)  分類號：   Keywords： Arabidopsis thaliana    cytosolic calcium    defence gene expression    hydrogen peroxide    OGA