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<LI> Study vector transmission specificity, biology, epidemiology, detection and management of whitefly-transmitted criniviruses. <LI> Address pathogenicity and infection physiology of BNYVV and other soil-borne viruses of sugarbeet. <LI> Develop virus-induced gene silencing for control of curtoviruses in tomato and sugarbeet. <LI> Identify and address problems associated with emerging and re-emerging viruses affecting sugarbeet and vegetable production in the United States, develop detection technologies for these viruses, and work toward effective management.
APPROACH: Evaluate factors contributing to the specificity of crinivirus transmission by whitefly vectors. Insect proteins will be separated and tested for interaction with whole virus and individual and combinations of virus proteins expressed in vitro. We will also conduct genetic and biological characterization of the criniviruses Lettuce chlorosis virus and Cucurbit yellow stunting disorder virus, and develop improved methods for detection and differentiation of criniviruses. Examine virus-host interactions, including differential protein expression and pathway activation in healthy sugarbeet and in sugarbeet infected with BNYVV, the causal agent of rhizomania. Studies will involve fractionation and separation of proteins and protein-protein binding studies. Attempt to develop infectious clones of BNYVV and BSBMV, and use these for generation of recombinant and pseudo-recombinant viruses that elucidate the viral genetic components responsible for BNYVV pathogenicity in sugarbeet, and increased disease severity during co-infection. Monitor for the emergence of BNYVV variants capable of overcoming known sources of resistance throughout the US beet industry using standard methods developed previously by our laboratory, and develop new methods for differentiation of resistance breaking isolates. Gene silencing constructs will be designed for control of curtoviruses in tomato and sugarbeet. Silencing constructs will be delivered in testing using either a virus-based vector carrying silencing constructs, or by delivery using Agrobacterium tumefaciens, and will be expressed as small interfering RNAs (siRNA). Identify and address problems associated with emerging and re-emerging viruses affecting sugarbeet and vegetable production in the United States, develop detection technologies for these viruses, and work toward effective management. This will involve biological, molecular and serological analyses including development of rapid detection tools, genetic characterization, vector identification and identification of factors contributing to virus emergence. (IBC info pending). Replaces 5305-22000-010-00D (3/07).