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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 tentaculata Kröber & Marwitz 1993 (Oomycetes, Pythiales)
Notes: Close to Phytophthora multivesiculata based on molecular analysis (Kroon et al. 2004).
Distribution: Europe (Spain, Germany).
Substrate: Roots, stems.
Disease Note: Root rot, stem rot. Heavily infected plants are killed (Kroeber & Marwitz, 1993).
Host: Chrysanthemum spp., Verbena, Santolina (Asteraceae).
Supporting Literature:
Erwin, D.C., and Ribeiro, O.K. 1996. Phytophthora Diseases Worldwide. APS Press, St. Paul, Minnesota, 562 pages.
Kroeber, H., and Marwitz, R. 1993. [Phytophthora tentaculata sp. nov. and Phytophthora cinnamomi var. parvispora var. nov., two new fungi from ornamental plants in Germany. Z. Pflanzenkrankh. Pflanzenschutz. 100: 250-258
Kroon, L.P.N.M., Bakker, F.T., van den Bosch, G.B.M., Bonants, P.J.M., and Flier, W.G. 2004. Phylogenetic analysis of Phytophthora species based on mitochondrial and nuclear DNS sequences. Fungal Genet. Biol. 41: 766-782
Updated on Jun 06, 2006
P. tentaculata is classified in group I (Stamps et al. 1991) because of its production of papillate sporangia and paragynous antheridia. Morphology is shown in Figure 1. See Tables 4.2 and 4.3 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for tabular keys.
1. Mycelium
On carrot agar, mycelium is arachnoid (like a spider web). Hyphal swellings are relatively small and occur where mycelium branches.
2. Chlamydospores
Chlamydospores are intercalary or terminal, spherical, thin-walled, and 10 to 45 µm in diameter (average 26.6 µm).
3. Sporangia
Sporangia are papillate; some are bipapillate. They are spherical or ovoid to obpyriform; some are distorted. A few are caducous with a short pedicel. They are 10 to 81 x 13 to 52 µm (average 35.7 x 27.4 µm); the length-breadth ratio is 1.30:1.
4. Sex Organs
P. tentaculata is homothallic. Oogonia form abundantly in culture and are 20 to 49 µm in diameter (average 34.0 µm). One to two, rarely three, paragynous antheridia (16.3 x 11.9 µm) are attached to the oogonium; a few are amphigynous. Antheridia are diclinous (the oogonium and antheridium emanate from different hyphae). Antheridia stalks are long and sometimes branched. A few stalks completely encircle the oogonium (Figure 1d). Some stalks have tooth-shaped projections. Oospores are spherical, hyaline, aplerotic, and 14 to 38 µm in diameter (average 28.1 µm).
5. Growth Temperatures
The minimum temperature for growth is 7oC, optimum 15 to 25oC, and maximum 32oC. The growth rate is 3 to 5 mm per day at optimum temperature.
6. Distinguishing Characteristics
In group I, P. tentaculata differs from P. cactorum by production of hyphal swellings, the different shape of sporangia, and by its low number of caducous sporangia. P. cactorum sporangia are nearly all caducous. P. tentaculata has larger oogonia and oospores than P. cactorum and also differs from P. clandestina in that it produces chlamydospores whereas P. clandestina does not. P. tentaculata also differs from P. pseudotsugae, which does not produce chlamydospores.
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
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