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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Research Project #432634

Research Project: Biologically Based Technologies for Control of Soil-Borne Pathogens of Vegetables and Ornamentals

Location: Sustainable Agricultural Systems Laboratory

Project Number: 8042-21220-181-00-D
Project Type: In-House Appropriated

Start Date: Jun 7, 2017
End Date: Jun 6, 2022

Objective:
Objective 1. Develop diagnostics for detection and differentiation of soil-borne sclerotial fungi. Sub-objective 1A. Identify and differentiate Rhizoctonia (sensu lato) pathogens by developing genome fingerprint-based markers. Sub-objective 1B. Use functional omics approaches to discover and develop novel molecular markers for virulence, host specificity, and identification of Rhizoctonia solani. Sub-objective 1B1. Compare transcriptomes of Rhizoctonia solani anastomosis groups (AGs) to determine if differences and commonalities across and between AGs suggest clues to host-range and virulence. Sub-objective 1B2. Identify proteins involved in virulence through comparison of the proteomes of hypovirulent Rhizoctonia solani AG3 isolates with a virulent AG3 isolate. Sub-objective 1C. Develop a database of Rhizoctonia genome and transcriptome information. Objective 2. Develop control tactics for the soil-borne sclerotial fungi Rhizoctonia solani and Sclerotinia sclerotiorum and the soil-borne oomycete Pythium ultimum. Objective 3. Identify mechanisms involved in control of soil-borne sclerotial pathogens and the soil-borne oomycete Pythium ultimum by biological control agents and their natural products. Sub-objective 3A. Determine impact of multitactic disease control strategies on soil microbial communities. Sub-objective 3B: Use functional omics approaches to identify biological control mechanisms involved in control of sclerotial plant pathogens. Sub-objective 3C. Identify compounds in ethanol extract of S. marcescens responsible for control of damping-off of cucurbits caused by P. ultimum, other oomycetes, and fungi.

Approach:
Omics (genomics, transcriptomics, proteomics) approaches will be employed to develop technologies for detection and identification of Rhizoctonia solani isolates so that appropriate control measures for specific R. solani isolates can be chosen for use in grower fields. Basic microbiology techniques will be used to develop new biologically based control measures, and combinations of control measures (biological controls, cover crops, chemical pesticides), for multiple pathogens (R. solani, Sclerotinia sclerotiorum, Pythium ultimum) over varied field conditions. Molecular biology and biochemistry approaches will be used to determine how existing biological controls control R. solani, S. sclerotiorum, and P. ultimum. Analysis of the rhizosphere microbiome using molecular techniques will determine the impact of these control measures on the rhizosphere microbial community. Transcriptomic and proteomic approaches will be used to identify genes and enzymes involved in degradation of sclerotia of S. sclerotiorum and other sclerotial pathogens by mycoparasitic biological control agents. Compounds in ethanol extract of Serratia marcescens responsible for control of damping-off of cucurbits caused by P. ultimum, other oomycetes, and fungi will be identified using biochemical and genetic approaches. Successful completion of this project will yield natural product chemistries, such as prodigiosin, for disease control and genes that can be used to screen for effective microbial biological control agents.