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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sugarbeet and Potato Research » Research » Research Project #422872

Research Project: Molecular Approaches for Improved Cercospora Leaf Spot Control in Sugarbeet

Location: Sugarbeet and Potato Research

Project Number: 3060-22000-047-000-D
Project Type: In-House Appropriated

Start Date: Mar 14, 2012
End Date: Mar 13, 2017

Objective 1: Identify and characterize virulence factors of Cercospora beticola. Sub-objective 1.A: Characterize the genome sequence of Cercospora beticola with emphasis on effector prediction. Sub-objective 1.B: Identify Cercospora beticola effectors induced during colonization of sugarbeet using next generation sequencing. Sub-objective 1.C: Identify effector proteins secreted by Cercospora beticola using proteomic techniques. Objective 2: Identify molecular markers in sugarbeet that are associated with the resistance response to Cercospora beticola. Sub-objective 2.A: Identify sugarbeet genes differentially expressed during the compatible and incompatible interaction using next generation sequencing. Sub-objective 2.B: Quantify defense-related hormone levels in sugarbeet during the compatible and incompatible interaction. Objective 3: Determine feasibility and validate new high-throughput PCR-based methods to detect fungicide resistance to aid in fungicide management programs. Sub-objective 3.A: Clone and sequence genes encoding the targets for demethylation inhibitor (DMI) or Qo inhibitor (QoI) fungicides in Cercospora beticola. Sub-objective 3.B: Analyze sequences of genes encoding fungicide targets to determine if mutations correlate with fungicide resistance and assess whether such mutations can be identified using PCR-based technology to identify resistant isolates in field populations. Objective 1 addresses current knowledge gaps in the pathology of Cercospora beticola by identifying effectors using genomic, transcriptomic, and proteomic approaches. This knowledge is particularly useful in conjunction with Objective 2, which seeks to identify sugarbeet resistance mechanisms using transcript and hormone profiling strategies that will aid in the development of improved molecular markers for Cercospora leaf spot resistance and/or susceptibility. Objective 3 will focus on the molecular basis of fungicide resistance, which may lead to novel means of identifying resistance in pathogen populations to improve fungicide efficacy.

The $2.1 billion U.S. sugarbeet industry is the primary provider of domestic sucrose. Sugarbeet provides an important source of stable, environmentally safe, and low-cost dietary carbohydrate to the public. In addition, beet sugar production and allied industries are an important source of employment regionally and nationally. Yield and quality losses are primarily a result of disease. These losses, in conjunction with expenses associated with pesticide application, cost the U.S. sugarbeet industry up to $150 million annually. The most important foliar disease of sugarbeet in the U.S. is Cercospora leaf spot, caused by the fungus Cercospora beticola. Despite the agricultural importance of this pathogen, stable genetic resistance does not exist and disease is often controlled through application of pesticides. Critical information is lacking on the basic biology of the sugarbeet-C. beticola interaction and the molecular basis of fungicide resistance. The goals of this project are to identify virulence factors of C. beticola, identify molecular markers in sugarbeet that are involved in the regulation of the response to Cercospora leaf spot, and determine if molecular methods can be utilized to detect fungicide resistance in C. beticola populations to aid in fungicide resistance management. This project utilizes state-of-the-art technology with results that will be utilized by all sectors of the sugarbeet industry from growers to processors. The concepts and discoveries generated by this research will lead to a more thorough understanding of sugarbeet pathology as well as host-pathogen interactions that negatively affect worldwide production agriculture.