Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: September 9, 2003
Publication Date: January 1, 2004
Citation: Hilf, M.E. 2004. Citrus tristeza virus: Evolution in a host-limited pathosystem. Phytopathology. 94:S131. Technical Abstract: Citrus tristeza virus(CTV) is a major viral pathogen of citrus, with a natural and experimental host range confined to members of the family Rutaceae, including the economically important genus Citrus. Experimental and agricultural paths of distribution of CTV are transmission by aphids and graft propagation of infected plant material. Analysis of the genomic sequences of five CTV strains suggested that three strains evolved wholly from a common ancestor while two strains appeared to be recombinants between contemporary strains and two different species of closterovirus. The genomic positions of suspected points of recombination and the conserved nucleotide sequence of the 3' terminal genes suggests that these genes are maintained as a cluster or module, possibly by providing cell-to-cell and long distance movement functions in Citrus hosts. Recombination thus may provide a method of increasing genetic variability in this host-limited virus, creating new strains of CTV by linking genes competent for movement in Citrus with genes from other viruses competent for replication but not movement in Citrus.