title: Genetic diversity and a PCR-based method for Xanthomonas axonopodis detection in passion fruit.
abstract: Xanthomonas axonopodis pv. passiflorae causes bacterial spot in passion fruit. It attacks the purple and yellow passion fruit as well as the sweet passion fruit. The diversity of 87 isolates of pv. passiflorae collected from across 22 fruit orchards in Brazil was evaluated using molecular profiles and statistical procedures, including an unweighted pair-group method with arithmetical averages-based dendrogram, analysis of molecular variance (AMOVA), and an assigning test that provides information on genetic structure at the population level. Isolates from another eight pathovars were included in the molecular analyses and all were shown to have a distinct repetitive sequence-based polymerase chain reaction profile. Amplified fragment length polymorphism technique revealed considerable diversity among isolates of pv. passiflorae, and AMOVA showed that most of the variance (49.4%) was due to differences between localities. Cluster analysis revealed that most genotypic clusters were homogeneous and that variance was associated primarily with geographic origin. The disease adversely affects fruit production and may kill infected plants. A method for rapid diagnosis of the pathogen, even before the disease symptoms become evident, has value for producers. Here, a set of primers (Xapas) was designed by exploiting a single-nucleotide polymorphism between the sequences of the intergenic 16S-23S rRNA spacer region of the pathovars. Xapas was shown to effectively detect all pv. passiflorae isolates and is recommended for disease diagnosis in passion fruit orchards.
authors.affiliation: Universidade de São Paulo, Escola Superior de Agricultura Luiz de Queiroz, Departamento de Genética, P.O. Box 83, 13400-970 Piracicaba, Brazil.
authors.forename: C F
authors.initials: CF
authors.lastname: Munhoz
authors.forename: B
authors.initials: B
authors.lastname: Weiss
authors.forename: L R
authors.initials: LR
authors.lastname: Hanai
authors.forename: M I
authors.initials: MI
authors.lastname: Zucchi
authors.forename: M H P
authors.initials: MH
authors.lastname: Fungaro
authors.forename: A L M
authors.initials: AL
authors.lastname: Oliveira
authors.forename: C B
authors.initials: CB
authors.lastname: Monteiro-Vitorello
authors.forename: M L C
authors.initials: ML
authors.lastname: Vieira
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D001938:Brazil; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D021903:DNA, Ribosomal Spacer; D014644:Genetic Variation; D005843:Geography; D029598:Passiflora / Q000235:genetics / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014774:Virulence; D053532:Xanthomonas axonopodis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S