Identification and Differentiation of Verticillium Species and V. longisporum Lineages by Simplex and Multiplex PCR Assays

PLoS One. 2013 Jun 18;8(6):e65990. doi: 10.1371/journal.pone.0065990. Print 2013.

Abstract

Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae), a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex) PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex) PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers.

Publication types

  • Validation Study

MeSH terms

  • DNA, Fungal / genetics
  • Phylogeny
  • Polymerase Chain Reaction / methods*
  • Sequence Homology, Nucleic Acid
  • Verticillium / classification*
  • Verticillium / genetics

Substances

  • DNA, Fungal

Grants and funding

Financial support for this research was provided by the California Leafy Greens Board (www.caleafygreens.ca.gov/) (contracts 2011-05 and 2011-06) and the United States Department of Agriculture–National Institute of Food and Agriculture (USDA-NIFA) (www.csrees.usda.gov/fo/specialtycropresearchinitiative.cfm) (grant# 2010-51181-21069). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.