Archives of Virology (2001) 146, 27-40

M.A. Ayllón, C. López, J. Navas-Castillo, S.M. Garnsey, J. Guerri, R. Flores and P. Moreno (2001)
Polymorphism of the 5' terminal region of Citrus tristeza virus (CTV) RNA: Incidence of three sequence types in isolates of different origin and pathogenicity
Archives of Virology 146 (1), 27-40
Abstract: Sequences of the 5' terminal region of the genomic RNA from eight isolates of Citrus tristeza virus (CTV) were previously classified into three types (I, II and III), with intragroup sequence identity higher than 88% and intergroup sequence identity as low as 44%. Sequencing of an additional 58 cDNA clones from 15 virus isolates showed that all sequences could be unequivocally assigned to one of the three types previously established. The relative frequency of each sequence type was assessed in 57 CTV isolates of different geographic origin and pathogenic characteristics by RT-PCR with sets of type-specific primers using CTV dsRNA as template. None of the isolates yielded amplification of the type I or II sequences alone, but in 19 of them type III sequences were the only amplification product detected. Within isolates containing more than one sequence type, eight had type II and III sequences, 11 had type I and III sequences, and 19 had sequences of the three types. Isolates containing only type III sequences caused only mild to moderate symptoms in Mexican lime, an indicator species for most CTV isolates, whereas isolates causing stem pitting in sweet orange an/or grapefruit, generally contained sequences type II. None of the sequence types could be traced to a precise geographic area, as all types were detected in isolates from at least nine of the 12 countries from which samples were taken.
(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): Maria A. Ayllon, José Guerri, Carmelo Lopez, Jesús Navas-Castillo

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	Citrus (genus)