EPPO-Q-bank

A database to support plant pest diagnostic activities

Methodologies - Phyllosticta and Guignardia

DNA sequences

Genomic DNA of the isolates was extracted using commercial DNA isolation kits.

Primer sequences and publication references for the primers can be obtained from the Primer list web page. The following loci and primers were used:

  • 5.8S nrRNA gene with the two flanking internal transcribed spacers (ITS)
    Primer pairs ITS1F or ITS-5 or V9G + ITS-4 or LR5 For a detailed protocol for amplification of the ITS region, please see the Molecular Decision Scheme. The ITS1F primer is fungal-specific and can be used for selective amplification of pure fungal material present on host material.
  • Partial 28S nrRNA gene (LSU)
    LR0R (Rehner & Samuels, 1994) + LR5 (Vilgalys & Hester, 1990) or LSU1Fd (Crous et al., 2009b) + LR5 (Vilgalys & Hester, 1990)
  • Partial actin gene (ACT)
    ACT-512F (Carbone & Kohn, 1999) + ACT-783R (Carbone & Kohn, 1999)
  • Partial glyceraldehyde-3- phosphate dehydrogenase gene (GAPDH)
    Primer pair Gpd1-LM + Gpd2-LM (Myllys et al., 2002); and for Phyllosticta citricarpa isolates GDF1 (Guerber et al., 2003) + GPDHR2 (Glienke et al., 2011)
  • Partial translation elongation factor 1-alpha gene (TEF)
    Primer pair EF1-728F (Carbone & Kohn, 1999) + EF-2 (O'Donnell et al., 1998) or EF1-728F (Carbone & Kohn, 1999) + EF1-986R (Carbone & Kohn, 1999)

The standard amplification reactions were performed in a 2720 Thermal Cycler (Applied Biosystems, Foster City, California) in a total volume of 25 μl. The PCR mixture contained 2 μl diluted genomic DNA (25-40 ng), 0.1 μM of each primer, 1x PCR buffer (Colorless GoTaq Flexi buffer), 2 mM MgCl2, 20 μM dNTP mix, 5.6% v/v DMSO (optional depending whether other Taq is used) and 0.12 μl Taq DNA polymerase (Promega GoTaq Flexi, 5 U/μl ). Conditions for amplification of loci consisted of an initial denaturation step of 5 min at 94 °C, followed by 40 cycles of 45 s at 94 °C, 30 s at 52 °C and 90 s at 72 °C, and a final extension step of 7 min at 72 °C. Amplicons were sequenced with both forward and reverse primers to ensure good quality sequences.

For the approximately 1 kb fragment of GAPDH of the Phyllosticta citricarpa isolates, the amplification reactions were performed in a 2720 Thermal Cycler (Applied Biosystems, Foster City, California) in a total volume of 25 μl.The PCR mixture contained 2 μl diluted genomic DNA (25-40 ng), 0.12 μM of each primer, 1x PCR buffer (Colorless GoTaq Flexi buffer), 2.5 mM MgCl2, 40 μM dNTP mix, and 0.12 μl Taq DNA polymerase (Promega GoTaq Flexi, 5 U/μl ). Conditions for amplification of loci consisted of an initial denaturation step of 5 min at 95 °C, followed by 35 cycles of 30 s at 95 °C, 45 s at 50 °C and 90 s at 72 °C, and a final extension step of 7 min at 72 °C.

References