Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2008
Publication Date: 12/27/2009
Citation: Goradia, L., Hartman, G.L., Daniel, S. 2009. Evaluation of Glyphosate-Resistant Soybean Cultivars for Resistance to Bacterial Pustule. European Journal of Plant Pathology. 124:331-335. Interpretive Summary: Bacterial pustule of soybean is a common disease in many soybean-growing areas of the world. Commercial soybean cultivars were evaluated for resistance to bacterial pustule. Three experiments were completed to evaluate resistance. Some of the glyphosate-tolerant soybean cultivars were resistant to bacterial pustule, but not at 100% frequency. This means that bacterial pustule outbreaks could occur when a susceptible cultivar is planted and conditions are conducive for bacterial pustule development. This information is useful to the soybean industry, and to researchers working on disease resistance.
Technical Abstract: Xanthomonas axonopodis pv. glycines causes bacterial pustule of soybean, which is a common disease in many soybean-growing areas of the world and is controlled by a single recessive gene that was commonly found in many conventional glyphosate-sensitive soybean cultivars. Since glyphosate-resistant cultivars are most commonly planted today, there has been no information about whether these new cultivars have bacterial pustule resistance. The goal of this study was to screen glyphosate-tolerant soybean cultivars for resistance to X. axonopodis pv. glycines. Three experiments were completed to evaluate resistance. Experiment 1 evaluated 525 soybean cultivars; many were resistant (no detectable symptoms) although 152 (~29%) developed some bacterial pustule. In experiment 2, three strains of X. axonopodis pv. glycines produced symptoms on three susceptible cultivars with one strain causing less disease severity than the other two. In a third experiment, 45 cultivars were inoculated with one strain of X. axonopodis pv. glycines. A range of disease severities developed with five cultivars (11%) having disease severity ratings as high as or worse than those on a susceptible check cultivar. Overall, these results suggested that resistance to bacterial pustule occurs in the glyphosate-tolerant soybean cultivars, but not at 100% frequency, which means bacterial pustule outbreaks could occur when a susceptible cultivar is planted and conditions are conducive for bacterial pustule development.