US-2346-93

Publications

Achievements

Citrus Tristeza Virus: Molecular Approaches to Cross Protection	Budget	Duration
	$300,000	3 years

	Dawson, W.O.	U Florida
	Bar-Joseph, M.	ARO, Min. Ag.
	Niblett, C.L.	U Florida
	Gafny, R.	ARO, Min. Ag.
	Lee, R.F.	U Florida
	Mawassi, M.	ARO, Min. Ag.

Final Report Abstract
Citrus tristeza virus (CTV) has the largest genomes among RNA viruses of plants. The 19,296-nt CTV genome codes for eleven open reading frames (ORFs) and can produce at least 19 protein products ranging in size from 6 to 401 kDa. The complex biology of CTV results in an unusual composition of CTV-specific RNAs in infected plants which includes multiple defective RNAs and mixed infections. The complex structure of CTV populations poses special problems for diagnosis, strain differentiation, and studies of pathogenesis. A manipulatable genetic system with the full-length cDNA copy of the CTV genome has been created which allows direct studies of various aspects of the CTV biology and pathology. This genetic system is being used to identify determinants of the decline and stem-pitting disease syndromes, as well as determinants responsible for aphid transmission.