title: Differentiation of strains of Xylella fastidiosa by a variable number of tandem repeat analysis.
abstract: Short sequence repeats (SSRs) with a potential variable number of tandem repeat (VNTR) loci were identified in the genome of the citrus pathogen Xylella fastidiosa and used for typing studies. Although mono- and dinucleotide repeats were absent, we found several intermediate-length 7-, 8-, and 9-nucleotide repeats, which we examined for allelic polymorphisms using PCR. Five genuine VNTR loci were highly polymorphic within a set of 27 X. fastidiosa strains from different hosts. The highest average Nei's measure of genetic diversity (H) estimated for VNTR loci was 0.51, compared to 0.17 derived from randomly amplified polymorphic DNA (RAPD) analysis. For citrus X. fastidiosa strains, some specific VNTR loci had a H value of 0.83, while the maximum value given by specific RAPD loci was 0.12. Our approach using VNTR markers provides a high-resolution tool for epidemiological, genetic, and ecological analysis of citrus-specific X. fastidiosa strains.
authors.affiliation: Centro de Citricultura Sylvio Moreira, Instituto Agronômico, CEP 13490-970, Cordeirópolis, São Paulo, Brazil. helvecio@centrodecitricultura.br
authors.forename: H D
authors.initials: HD
authors.lastname: Coletta-Filho
authors.forename: M A
authors.initials: MA
authors.lastname: Takita
authors.forename: A A
authors.initials: AA
authors.lastname: de Souza
authors.forename: C I
authors.initials: CI
authors.lastname: Aguilar-Vildoso
authors.forename: M A
authors.initials: MA
authors.lastname: Machado
mesh_terms: D015373:Bacterial Typing Techniques; D002957:Citrus / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics*; D018598:Minisatellite Repeats / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D004269:DNA, Bacterial