Location: Foreign Disease-Weed Science Research
Project Number: 8044-22000-048-000-D
Project Type: In-House Appropriated
Start Date: Mar 26, 2022
End Date: Mar 25, 2027
Objective 1: Develop genomic sequence resources and broad range nucleic acid and antibody-based diagnostics for novel emerging and invasive vectored plant pathogens. (NP303, C1, PS1A, PS1B) Sub-objective 1.A: Development of rapid diagnostics for bacterial blight of grapevine caused by Xylophilus ampelinus. Sub-objective 1.B: Identify and characterize emergent and invasive plant viruses and bacteria with potential for agronomic damage, and develop genome sequence resources. Sub-objective 1.C: Develop immunodiagnostic reagents and field-deployable diagnostic assays for specific and sensitive detection of exotic, emergent, and quarantine plant viruses. Sub-objective 1.D: Collect and characterize foreign and emerging bacterial plant pathogens. Objective 2: Investigate the relationship of pathogen biology and ecology to disease expression of novel emerging and invasive vectored plant pathogens. (NP303, C2, PS2A, PS2B) Sub-objective 2.A: Investigate virus determinants of resistance-breaking. Sub-objective 2.B: Analyze virus protein expression and function in pathogenicity in single and mixed infections. Sub-objective 2.C: Identify proteins and genes involved in virulence during X. fastidiosa subsp. pauca infection of citrus. Sub-objective 2.D: Test susceptibility of New World Vitis species and hybrids to bacterial blight of grapevine caused by Xylophilus ampelinus. Sub-objective 2.E: Genetic determinants of toxin production in Rathayibacter toxicus. Objective 3: Understand the role of the vector in pathogen retention and transmission of viruses and bacteria. (NP303, C2, PS2B, PS2D) Sub-objective 3.A: Develop sequence data resources for selected insect vectors and utilize data for refined taxonomic identification assays. Sub-objective 3.B: Evaluate virus transmission determinants and test candidate molecules for transmission disruption.
Using specialized containment facilities, we will research key questions to assist in detecting and managing emerging, foreign, and invasive viral and bacterial diseases which threaten U.S. agriculture. Our research aims are to 1) develop sequence data, collections, and needed diagnostic tools for new pathogens; 2) elucidate basic molecular biology of virulence, toxicity, and pathogenicity of target pathogens; and 3) develop tools to characterize important vector populations and methods to block virus transmission. Target diseases include: foreign bacterial blight of grapevine, caused by Xylophilus ampelinus; citrus variegated chlorosis, caused by Xyllella fastidiosa; foreign and emergent maize lethal necrosis (MLN), caused by mixed infections of potyviruses in combination with the rapidly emerging maize chlorotic mottle virus (MCMV) driven by its corn thrips (Frankliniella williamsi) vector; U.S.-emergent cotton leafroll dwarf disease, caused by cotton leafroll dwarf virus (CLRDV); foreign disease caused by maize yellow mosaic virus (MaYMV/MYDV-RMV2); foreign rice tungro disease and other waikavirus-caused diseases; and foreign annual ryegrass toxicity (ARGT) livestock poisoning caused by the Select Agent Rathayibacter toxicus. Our research plan also includes the flexibility to respond to new pathogens that may emerge. Research will result in the development of sequence data, diagnostic tools, pathogen collections, and basic biological information about pathogenicity, toxicity and resistance-breaking, as well as tools to assess corn thrips populations and block spread of cotton leafroll dwarf disease.