Disease Resistance Conferred by Expression of a Gene Encoding H 2 O 2 -Generating Glucose Oxidase in Transgenic Potato Plants

Abstract

Plant defense responses to pathogen infection involve the production of active oxygen species, including hydrogen peroxide (H2O2). We obtained transgenic potato plants expressing a fungal gene encoding glucose oxidase, which generates H2O2 when glucose is oxidized. H2O2 levels were elevated in both leaf and tuber tissues of these plants. Transgenic potato tubers exhibited strong resistance to a bacterial soft rot disease caused by Erwinia carotovora subsp carotovora, and disease resistance was sustained under both aerobic and anaerobic conditions of bacterial infection. This resistance to soft rot was apparently mediated by elevated levels of H2O2, because the resistance could be counteracted by exogenously added H2O2-degrading catalase. The transgenic plants with increased levels of H2O2 also exhibited enhanced resistance to potato late blight caused by Phytophthora infestans. The development of lesions resulting from infection by P. infestans was significantly delayed in leaves of these plants. Thus, the expression of an active oxygen species-generating enzyme in transgenic plants represents a novel approach for engineering broad-spectrum disease resistance in plants.

Inhibition of the Plastidic ATP/ADP Transporter Protein Primes Potato Tubers for Augmented Elicitation of Defense Responses and Enhances Their Resistance against Erwinia carotovora

“…1). This assumption is supported by the finding that heterologous expression of an apoplastic Glc oxidase, which causes constitutively enhanced H 2 O 2 levels, confers strongly enhanced E. carotovora resistance to potato tubers (Wu et al, 1995). However, other factors that might also contribute to the improved E. carotovora resistance should also be kept in mind.…”

Involvement of Reactive Oxygen Species, Glutathione Metabolism, and Lipid Peroxidation in the Cf-Gene-Dependent Defense Response of Tomato Cotyledons Induced by Race-Specific Elicitors of Cladosporium fulvum

“…A role for H,O, as an antimicrobial agent (Kim et al, 1988;Wu et al, 1995), a substrate for lignin synthesis (Gross et al, 1977), and a signal molecule for the hypersensitive cell death response (Levine et al, 1994), phytoalexin accumulation (Edwards et al, 1991;Guo et al, 1993), and SA biosynthesis (Leon et al, 1995) has already been demonstrated. But ROI levels must be controlled to avoid damage to the surrounding noninvaded tissue whose viability may be required for the coordinated defense response.…”

Response to Xanthomonas campestris pv.vesicatoria in Tomato Involves Regulation of Ethylene Receptor Gene Expression

“…One of the first differences is the greater increase in reactive oxygen intermediates observed during an incompatible interaction (Keppler et al, 1989;Orlandi et al, 1992). This oxidative burst may kill the pathogen directly (Keppler et al, 1989;Wu et al, 1995) or limit its spread by killing infected plant cells (Greenberg et al, 1994) and inducing cross-linkage of cell wall proteins (Bradley et al, 1992;Brisson et al, 1994). During an incompatible interaction, cell walls are also strengthened through increased deposition of hydroxy-Pro-rich glycoproteins (Showalter et al, 1985), callose (Parker et al, 1993), and lignin (Moerschbacher et al, 1990).…”