Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2007
Publication Date: N/A
Interpretive Summary: Citrus tristeza virus (CTV) causes several destructive and economically damaging diseases of citrus in most citrus producing countries. Populations of CTV show great genetic diversity and diverse disease symptoms. This work proposes how genetic recombination might be responsible for this genetic diversity and how it might be related to the diverse symptoms caused by CTV.
Technical Abstract: Citrus tristeza virus (CTV) isolates T36, T68-1 and NS25 showed phylogenetic incongruities between sequences involved in viral RNA replication and those involved in movement and other viral functions. This incongruity was not found in the sequences of isolates T3, T30, T385, VT and T318A. Distance analysis of the replication sequences of T36, T68-1 and NS25 showed these sequences were distinct from each other and from replication sequences of T3, T30, T385, VT and T318A, which formed a cluster of related replication sequences. Distance analysis indicated that sequences not associated with replication were highly similar among all CTV sequences examined. Phylogenetic profiling identified potential recombination points in the genomes of T36, T68-1 and NS25, indicating that recombination joined disparate replication sequences with highly conserved sequences for movement and other virus functions. CTV is restricted primarily to host plants in the genus Citrus and the evidence suggests that the CTV genome has evolved into two functional modules with major increases in genetic diversity in the replication module occurring when more distantly related replication sequences are introduced into infected citrus trees and recombination occurs with these more conserved CTV sequences for movement and other virus functions associated with a CTV population already present in these infected citrus trees.