Virus Genes (2006) 32, 119-128

María A. Ayllón, Luis Rubio, Vicente Sentandreu, Andrés Moya, José Guerri and Pedro Moreno (2006)
Variations in two gene sequences of Citrus tristeza virus after host passage
Virus Genes 32 (2), 119-128
Abstract: We estimated genetic variation in two groups of Citrus tristeza virus (CTV) isolates: one of them (isolates T385, T317, T318 and T305) derived from a Spanish source by successive host passages, and the other (isolates T388 and T390), obtained after aphid transmission of a Japanese source. The population structure of these isolates had been characterized by single-strand conformation polymorphism analysis of genes p18 and p20. The nucleotide sequences of representative haplotypes of each isolate and gene were used to estimate genetic diversity within and between isolates and to evaluate genetic differentiation between populations. Phylogenetic analysis of p18 and p20 sequence variants showed two main groups: one them included variants predominant in the severe isolates (T318, T305 and T388), and the other comprised variants present in both mild (T385, T317) and severe isolates. Most sequence variants of isolate T390 were not associated to these groups. In some isolates, within-isolate diversity was higher than diversity with other isolates because their population contained distantly related sequence variants, some of which were genetically close to variants predominant in the second isolate. Isolates T388 and T390 were genetically different for the two genes, as estimated by the F statistic. Furthermore, genetic differentiation between T385 and T317, T318 and T305 increased after each host passage. Our results suggest that aphid transmission and host passage may significantly alter the composition of CTV populations and thus be an important factor in their evolution.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Luis Rubio, Maria A. Ayllon, José Guerri

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Citrus tristeza virus		Spain (continental)
	Citrus tristeza virus		Japan