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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 drechsleri Tucker 1931 (Oomycetes, Pythiales)
Phytophthora erythroseptica var. drechsleri (Tucker) Sarej. 1936
= Pythium teratosporon Sideris 1932 Note: Synonymy based on Erwin & Ribeiro 1996, see also Waterhouse 1970.
Notes: Ho and Jong (1986) listed various synonyms as part of their broad species concept. They considered Phytophthora cryptogea to be synonymous with Phytophthora drechsleri Cooke et al. (2000) found the two species to be distinct based on molecular analysis. Phytophthora melonis and Phytophthora sinensis were also found to be distinct from P. drechsleri. Cooke (2000) also found that P. drechsleri is not closely related to P. cajani which should be considered a distinct species and not a f. sp. or variety of P. drechsleri.
Distribution: Cosmopolitan.
Substrate: Roots, stems, leaves, buds, flowers, fruits, tubers, bark of trunks.
Disease Note: Primarily a root pathogen but also attacks ripening fruit for various crops. Root rot, bark canker fruit rot, stem rot, seedling blight; see Erwin & Ribeiro (1996) for disease symptoms listed by host.
Host: 113 genera in 40 families.
Supporting Literature:
Cooke, D.E.L., Drenth, A., Duncan, J.M., Wagels, G., and Brasier, C.M. 2000. A molecular phylogeny of Phytophthora and related Oomycetes. Fungal Genet. Biol. 30: 17-32
Erwin, D.C., and Ribeiro, O.K. 1996. Phytophthora Diseases Worldwide. APS Press, St. Paul, Minnesota, 562 pages.
Ho, H.H., and Jong, S.C. 1986. A comparison between Phytophthora cryptogea and P. drechsleri. Mycotaxon 27: 289-319
Stamps, D.J. 1985. Phytophthora drechsleri. C.M.I. Descript. Pathog. Fungi Bact. 840: 1-2
Waterhouse, G.M. 1970. The genus Phytophthora de Bary. Mycol. Pap. 122: 1-59
Updated on Jun 06, 2006
A summary of the morphology and the diseases caused by P. erythroseptica is given by Stamps (1978c). P. erythroseptica was redescribed by Ho and Jong (1989b). See Tables 4.2 and 4.3 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for tabular keys. It is classified in group VI (Stamps et al. 1990). Morphology is shown in Figure 1.
1. Sporangia
Sporangia are nonpapillate and ellipsoid, ovoid, obpyriform, or distorted in shape, often with a constriction distal to the middle. They have tapered bases, germinate by internal proliferation, and are 43 to 69 μm long x 26 to 47 μm wide (average 44.2 x 27.2 μm). The length-breadth ratio averages 1.65:1. Sporangiophores are sympodial, branching immediately below the sporangium. Zoospores are released from sporangia after chilling of the aqueous culture (Vuji and Calhoun 1966).
2. Chlamydospores
Chlamydospores have not been found. Hyphal swellings (11-27 μm in diameter) are round or angular and form in chains or clusters in water.
3. Sex Organs
Antheridia are amphigynous, elongated, and cylindrical; oogonia are 30 to 46 μm in diameter (average 34.9 μm); oospores are aplerotic, 28 to 35 μm in diameter (average 30.5 μm), and homothallic. Oogonia with two, three, or four antheridia were observed by Gerrettson-Cornell (1985) but were not noted by Ho and Jong (1989b).
4. Growth Temperatures
Minimum temperature for growth is 2.5oC, optimum 27.5oC, and maximum 34oC.
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
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