Evaluation of Lysobacter enzymogenes C3 for control of soybean fungal diseases
Fungal and oomycete diseases can cause severe yield losses on soybean. These losses are typically managed by planting resistant cultivars, utilizing good cultural practices, and applying fungicides. However, because these methods rarely achieve complete control and demand is increasing for more environmentally-friendly management options, more research has focused on using biological control agents (BCA) to supplement conventional methods. One BCA that has shown biological control against various plant pathogens is Lysobacter enzymogenes C3 (LeC3), an ubiquitous bacterium that secretes numerous novel antimicrobials relevant to human drug therapies and crop protection. We first used in vitro assays to establish LeC3’s efficacy against the following soybean-pathogenic fungi and oomycetes: Cercospora sojina, Fusarium virguliforme, Macrophomina phaseolina, Phytophthora sojae, Pythium sylvaticum, Rhizoctonia solani, Septoria glycines, and Sclerotinia sclerotiorum. Our experiments confirmed previous reports that antagonism arises from a broad spectrum of inhibition activities. Next, we evaluated LeC3 as a biological control agent on soybean hosts. We first used a test tube assay to evaluate LeC3 by seed treatment against seedling root pathogens: F. virguliforme, P. sojae, P. sylvaticum, and R. solani. We also utilized a detached leaf assay to evaluate LeC3 by spray treatment against foliar and stem pathogens C. sojina and S. sclerotiorum, respectively. We next evaluated biological control in greenhouse conditions using LeC3 as seed or soil drench treatments against sudden death syndrome (caused by F. virguliforme) and seedling blight and root rot (caused by R. solani); and spray treatment against frogeye leaf spot (caused by C. sojina) and white mold/stem rot (caused by S. sclerotiorum). Our findings showed successful biological control against several soybean diseases.
biological control, biocontrol, lysobacter, enzymogenes, C3, soybean, fungal, pathogens, oomycetes, in vitro, greenhouse, bacteria
University of Illinois - Urbana-Champaign
Networked Digital Library of Theses and Dissertations
University of Illinois at Urbana-Champaign