title: Molecular test to assign individuals within the Cacopsylla pruni complex.
abstract: Crop protection requires the accurate identification of disease vectors, a task that can be made difficult when these vectors encompass cryptic species. Here we developed a rapid molecular diagnostic test to identify individuals of Cacopsyllapruni (Scopoli, 1763) (Hemiptera: Psyllidae), the main vector of the European stone fruit yellows phytoplasma. This psyllid encompasses two highly divergent genetic groups that are morphologically similar and that are characterized by genotyping several microsatellite markers, a costly and time-consuming protocol. With the aim of developing species-specific PCR primers, we sequenced the Internal Transcribed Spacer 2 (ITS2) on a collection of C. pruni samples from France and other European countries. ITS2 sequences showed that the two genetic groups represent two highly divergent clades. This enabled us to develop specific primers for the assignment of individuals to either genetic group in a single PCR, based on ITS2 amplicon size. All previously assigned individuals yielded bands of expected sizes, and the PCR proved efficient on a larger sample of 799 individuals. Because none appeared heterozygous at the ITS2 locus (i.e., none produced two bands), we inferred that the genetic groups of C. pruni, whose distribution is partly sympatric, constitute biological species that have not exchanged genes for an extended period of time. Other psyllid species (Cacopsylla, Psylla, Triozidae and Aphalaridae) failed to yield any amplicon. These primers are therefore unlikely to produce false positives and allow rapid assignment of C. pruni individuals to either cryptic species.
authors: INRA, UMR 0325 Biologie et Génétique des Interactions Plantes-Parasites, Campus International de Baillarguet, Montpellier, France.
authors: Jean
authors: J
authors: Peccoud
authors: Gérard
authors: G
authors: Labonne
authors: Nicolas
authors: N
authors: Sauvion
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers / Q000378:metabolism; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D056426:Genetic Loci; D005843:Geography; D006430:Hemiptera / Q000145:classification* / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D021903:DNA, Ribosomal Spacer
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