Phytophthora has been rebuilt to fix security-related problems and to restore GIS tools. These tools allow users to visualize the geospatial, temporal, and environmental contexts of Phytophthora discoveries. The next phase is to update species information and add data derived from large-scale surveys. If you have suggestions and requests to make the database better, please contact Seogchan Kang (sxk55@psu.edu).
Genus wide phylogeny for Phytophthora using four mitochondrial loci (cox2, nad9, rps10 and secY; 2,373 nucleotides). Maximum likelihood branch lengths shown. Numbers on nodes represent bootstrap support values for maximum likelihood (top), maximum parsimony (middle) and Bayesian posterior probabilities as percentages (bottom). Nodes receiving significant support (>95%) in all analysis are marked with an asterisk (*). Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).
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Phytophthora uliginosa T. Jung & E.M. Hansen 2002 (Oomycetes, Pythiales)
Distribution: Europe (Poland, Germany).
Substrate: Soil.
Disease Note: Aggressive root rot and dieback of oaks. Associated with oak decline.
Host: Quercus robur, Quercus petraea (Fagaceae).
Supporting Literature:
Jung, T., Hansen, E.M., Winton, L., Obwald, W. , and Delatour, C. 2002. Three new species of Phytophthora from European oak forests. Mycol. Res. 106: 397-411
Updated on Jun 26, 2006
Phytophthora uliginosa T. Jung & E. M. Hansen was isolated from soil samples taken around declining Q. robur and Q. petraea trees in Poland and Germany. In phylogenetic analysis P. uliginosa is in clade 7a with P. cambivora, P. fragariae, P. alni and P. europaea
1. Sporangia
Non-papillate sporangia with a flattened broad apex, a very thin apical thickening, and an extremely wide exit pore are formed in water. Empty sporangia are sometimes funnel-shaped with slightly curled walls towards the exit pore. Fully mature sporangia are mostly broad-ellipsoid or obpyriform, sometimes with an undulating wall or a conspicuous basal plug, averaging 49 ± 6.0 x 30 ± 4.2 µm (type isolate : 50 ± 6.7 x 32 ± 5.0 µm); length) breadth ratio is about 1.6. Sporangial proliferation is external or internal, sometimes nested. Sporangia form on loosely branched sporangiophores. Main and lateral hyphae are irregular in diameter, and short thick lateral hyphae without restricted base as well as irregular hyphal swellings are common in all isolates. In water, clusters of hyphae with chains of deltoid to irregular swellings are formed. Hyphae often taper towards a point where they suddenly become wider again; therefore, hyphal tips often appear arrowlike.
2. Chlamydospores
Not formed
3. Sex Organs
Phytophthora uliginosa is homothallic. The type isolate produced oogonia rarely after isolation from forest soil, but abundantly after reisolation from fine roots of artificially inoculated Q. robur. Oogonia from 3 isolates averaged 43 ± 4.4 µm (type isolate : 44 ± 4.6 µm) with isolate means ranging from 42 to 46 µm. Antheridia are paragynous, about 17 ± 3.3 x 13 ± 2.6 µm, and attached near the stalk. Plerotic and aplerotic oospores with thick walls (average 4 ± 0.7 µm) are found in all isolates, and average 39 ± 4.4 µm diameter with isolate means ranging from 38 to 40 µm.
4. Growth Temperatures
P. uliginosa grows about 2.0 mm/day and 2.5 mm/day in colony radius at optimum temperature (about 17 - 18° C) on CMA and V8A, respectively. Maximum temperature for growth is about 29° C with minimal at 3.5° C.
5. Growth Characteristics in Culture
The colony morphology on CMA, V8A and MEA is uniform without any growth pattern, with some aerial mycelium but not dome shaped. On PDA, P. uliginosa shows almost no growth. No pigment is produced on CHT agar.
6. Distinguishing Characteristics
Being homothallic with paragynous antheridia and non-papillate sporangia with a shallow apical thickening P. uliginosa belongs to morphological group V. It shares many morphological and growth features with members of the P. cambivora clade. Like P. europaea, P. uliginosa differs from other species in the clade in its combination of smooth-walled, homothallic oogonia with one-celled paragynous antheridia. P. uliginosa is distinguished from P. europaea by having larger oogonia without tapering base, larger oospores, wider exit pores, slower growth rates, lower optimum and maximum temperatures for growth, different colony morphologies on CMA, V8A, MEA and PDA, and different ITS-DNA sequences. Furthermore, it seems to be more aggressive to Q. robur than P. europaea. P. uliginosa is reported as Phytophthora 'species 5' in previous works (Jung et al. 2000).
P. uliginosa can cause root rot of Q. robur and Q. petraea. Recovery from soil is more successful during the cooler times of the year.
Jung, T., M. Hansen, E. M., Winton, L., Oswald, W. and Delatour, C. 2002. Three new species of Phytophthora from European oak forests Mycol. Res. 106: 397-411.
Jung, T., Blaschke, H. & Oûwald, W. (2000) Involvement of Phytophthora species in Central European oak decline and the effect of site factors on the disease. Plant Pathology 49:706-718.
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS. This species page was adapted from Jung et al. (2002).
Isolate list