Biological Invasions

, Volume 15, Issue 8, pp 1847–1861

Invaded range of the blackberry pathogen Phragmidium violaceum in the Pacific Northwest of the USA and the search for its provenance

  • Louise Morin
  • Don R. Gomez
  • Katherine J. Evans
  • Tara M. Neill
  • Walt F. Mahaffee
  • Celeste C. Linde
Original Paper

DOI: 10.1007/s10530-013-0413-3

Cite this article as:
Morin, L., Gomez, D.R., Evans, K.J. et al. Biol Invasions (2013) 15: 1847. doi:10.1007/s10530-013-0413-3

Abstract

Field surveys in 2006 confirmed that the exotic rust fungus Phragmidium violaceum was widespread on Rubus armeniacus and Rubus laciniatus in the Pacific Northwest of the USA. The origin and dispersal pattern of this obligate biotrophic pathogen in the USA were investigated by comparing the genetic diversity and structure of 27 isolates each from the USA and Europe, and 20 isolates from Australia where an invasion occurred in 1984. Analysis of 11 microsatellite loci revealed 74 unique genotypes, with the European population having a significantly higher level of allelic diversity and number of private alleles compared to populations from the USA and Australia. Principal coordinate analysis (PCA), analysis of molecular variance and pairwise comparisons of Φ confirmed a strong level of differentiation among continental populations, with little divergence between isolates from the USA and Europe, but a high level of differentiation between these isolates and those from Australia. These results were broadly supported by the Bayesian cluster analysis, which indicated that at K = 3 the clustering of the isolates corresponds to their geographic origin. Bayesian clustering, PCA as well as insignificant migration estimates from Europe to the USA suggest that the USA population is not a direct descendant from the European P. violaceum population. There was a weak association between genetic and geographic distance among the USA isolates, suggesting invasion was initially localized prior to dispersal or that the population may have been present for some time prior to first detection in 2005.

Keywords

Blackberry rust Genetic diversity Microsatellites Rubus armeniacus Rubus fruticosus aggregate Rubus laciniatus 

Copyright information

© © CSIRO (outside the USA) 2013

Authors and Affiliations

  • Louise Morin
    • 1
  • Don R. Gomez
    • 1
  • Katherine J. Evans
    • 2
  • Tara M. Neill
    • 3
  • Walt F. Mahaffee
    • 3
    • 4
  • Celeste C. Linde
    • 5
  1. 1.CSIRO Ecosystem SciencesCanberraAustralia
  2. 2.Perennial Horticulture Centre, Tasmanian Institute of AgricultureUniversity of TasmaniaNew TownAustralia
  3. 3.Horticultural Crops Research LaboratoryUnited States Department of Agriculture–Agricultural Research ServiceCorvallisUSA
  4. 4.Department of Botany and Plant PathologyOregon State UniversityCorvallisUSA
  5. 5.Evolution, Ecology and Genetics, Research School of BiologyAustralian National UniversityCanberraAustralia

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