Table 1. Morphological characteristics of ophiostomatoid fungi found in conductive tissues of Quercus robur in the Tellerman forest, Russia. Results are based on 30–50 measurements of each taxonomically informative morphological structure.
Characteristics O. fusiforme-like O. grandicarpum O. quercus
Perithecia  
   base diameter (µm) 100–250 350–500 160–220
   neck length (µm) 350–800 2000–8000 930–1600
Ostiolar hyphae present absent present
Ascospores  
   shape allantoid, no sheath orange section, possibly with sheath allantoid, no sheath
   size (µm) (4.5–5.0) × (1.0–1.5) (4.0–5.0) × (1.5–2.0) (3.9–5.2) × (1.3–2.0)
Anamorph sporothrix-like sporothrix-like sporothrix- and pesotum-like
Growth rate on malt extract agar (mm day–1) 1.3 ± 0.2 1.3 ± 0.2 4.0 ± 0.4
Colony morphology snow-white, fluffy, ascending light-grey, no aerial mycelia initially white, darkening with age
Substrate phloem аnd sapwood phloem phloem аnd sapwood
Culture collection no. CMW41130 CMW41131 CMW41129
GenBank acc. no  
   ITS KP289352 KP289353 KP289351
   β-tubulin KP289355 KP289356 KP289354
Table 2. Number of ophiostomatoid fungi in collected Quercus robur samples in Tellerman forest. In total of 286 wood samples were investigated during 2005–2009. More than one ophiostomatoid species were possible to find in the same wood sample.
Fungal species No. of wood samples with fungi Percentage of fungi (%)
In total
   Ophiostoma grandicarpum 15 5.2
   O. fusiforme-like 61 21.3
   O. quercus 93 32.5
Species present in the same sample
   O. grandicarpum alone 12 4.2
   O. fusiforme-like alone 31 10.8
   O. quercus alone 65 22.7
   O. grandicarpum + O. fusiforme-like 2 0.7
   O. grandicarpum + O. quercus 0 0
   O. fusiforme + O. quercus 27 9.4
   O. grandicarpum + O. fusiforme-like + O. quercus 1 0.4
Total 138 48.2
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Fig. 1. Phylogram obtained from ML analyses of the ITS regions. Isolate numbers of sequences obtained in this study are printed in bold type. The bootstrap support values for ML (normal type) and MP (bold type) above 70% are indicated at the nodes. Posterior probabilities (above 90%) obtained from BI are indicated by bold lines at the relevant branching points. * = bootstrap values lower than 70%. T = ex-type isolates. Scale bar = total nucleotide difference between taxa.

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Fig. 2. Phylogram obtained from ML analyses of the β-tubulin gene of species in the O. ulmi complex. Isolate numbers of sequences obtained in this study are printed in bold type. The bootstrap support values for ML (normal type) and MP (bold type) above 70% are indicated at the nodes. Posterior probabilities (above 90%) obtained from BI are indicated by bold lines at the relevant branching points. * = bootstrap values lower than 70%. T = ex-type isolates. Scale bar = total nucleotide difference between taxa.

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Fig. 3. Phylogram obtained from ML analyses of the β-tubulin gene of species in the S. schenckii–O. stenoceras complex. Isolate numbers of sequences obtained in this study are printed in bold type. The bootstrap support values for ML (normal type) and MP (bold type) above 70% are indicated at the nodes. Posterior probabilities (above 90%) obtained from BI are indicated by bold lines at the relevant branching points. * = bootstrap values lower than 70%. T = ex-type isolates. Scale bar = total nucleotide difference between taxa.

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Fig. 4. Brown necrosis caused by Ophiostoma quercus in the inner bark of young Quercus robur tree 10 months after the inoculation. Аgar blocks overgrown with the fungus mycelium served an inoculum. Necrosis size: length 47 mm; width 10 mm.

Table 3. Lesion sizes (x ± m, mm) in the phloem at the end of the inoculation experiment of young Quercus robur trees (size of the wound area is deducted from necrosis area).
Inoculation variant used in August 2010 Measured in September 2010 Measured in May 2011
  Lenght Lenght Width
Ophiostoma grandicarpum 1.7 ± 1.7 16.7 ± 8.8 0
O. fusiforme-like 10.3 ± 7.5 30.6 ± 8.5 4.1 ± 4.1
O. quercus 5.1 ± 2.3 69.1 ± 20.5* 11.1 ± 3.9
Sterile agar block 5.7 ± 4.7 9.0 ± 3.8 0
Control (wounding without inoculation) 0 3.3 ± 3.3 3.3 ± 3.3
*Significantly different from control (wounding without inoculation) according to Mann-Whitney test (P ≤ 0.05).