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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 lateralis Tucker & Milbrath 1942 (Oomycetes, Pythiales)
Distribution: New Zealand, North America (Canada, USA). Possibly introduced from France (Erwin & Ribeiro 1996).
Substrate: Roots, crowns.
Disease Note: Root and crown rot.
Host: Chamaecyparis lawsoniana (Lawson cypress aka Port Orford cedar, Cupressaceae), rarely, Taxus brevifolia (Pacific yew, Taxaceae). Hosts in other families can be infected when inoculated.
Supporting Literature:
Erwin, D.C., and Ribeiro, O.K. 1996. Phytophthora Diseases Worldwide. APS Press, St. Paul, Minnesota, 562 pages.
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
Tucker, C.M., and Milbrath, J.A. 1942. Root rot of Chamaecyparis caused by a species of Phytophthora. Mycologia 34: 94-103
Updated on Jun 15, 2006
P. lateralis is classified in group V (Stamps et al. 1990). See Tables 4.2 and 4.3 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for tabular keys. A description of the morphology of P. lateralis is given by G. Hall (1991c). Morphology is shown in Figure 1 and Figure 2.
1. Sporangia
Sporangia are nonpapillate and borne sympodially on simple sporangiophores; they are ovate, obovate, obpyriform, and often elongate or distorted in shape; 20 to 60 µm long x 12 to 20 µm wide (average 26 x 15 µm); in water, elongated necks occur; sporangia are persistent on the stalk (Tucker and Milbrath 1942). The length-breadth ratio varies from 1.6 to 1.9:1 (average 1.71:1). Sporangia formed most abundantly in weak agar media such as V8 juice (10 ml/liter), cornmeal (25 g/liter), or whole milk (20 ml/liter), especially when these media were made up with Hoagland\'s mineral solution instead of distilled water (Trione 1974). Sporangium formation was markedly increased by incubation of cultures under combined Blacklight Blue and Cool White fluorescent lamps (680 µWcm–2) continuously or for 12-h periods.
2. Hyphal Swellings
Hyphal swellings do not form, but the early stages of chlamydospore formation resemble hyphal swellings.
3. Chlamydospores
Chlamydospores are abundant in many agar media at temperatures between 15 and 25oC; they are terminal or intercalary, 20 to 77 µm in diameter (average 40 µm), and cinnamon brown in color when produced in cedar foliage agar (Trione 1974). Chlamydospore production was suppressed by light (Englander and Roth 1980).
4. Sex Organs
P. lateralis is homothallic. Antheridia are paragynous; oogonia are smooth, spherical, and terminal, 33 to 50 µm in diameter; oospores are plerotic with walls 6 µm thick, 28 to 46 µm in diameter (average 40 µm), and deeply pigmented; the color depends on the agar medium used, e.g., cinnamon colored in cedar foliage agar and amber in alfalfa agar medium. Oospores were formed most abundantly on agar of Port Orford cedar foliage (filtrate from 200 g of foliage steamed at 95oC for 1 h plus 15 g of glucose per liter of water) (Trione 1974).
5. Growth Temperatures
The minimum temperature for growth is 3oC, the optimum is 20oC, and the maximum is <26oC.
6. Distinguishing Characteristics
The formation of the chlamydospores, which are lateral on the mycelium, differs markedly from the clustered chlamydospores of other nonpapillate species such as P. cambivora, P. cinnamomi, P. cryptogea, P. drechsleri, and P. richardiae. The chlamydospores of P. lateralis are often sessile on the hyphae or appear to be supported by two hyphae (Figure 1).
P. cinnamomi can be distinguished from P. lateralis by the presence of a characteristic grapelike cluster of hyphal swellings and chlamydospores and the production of amyphigynous antheridia in dual cultures (heterothallic). P. lateralis produces paragynous antheridia in single culture (homothallic). P. cinnamomi grows at a higher maximum temperature (>30oC) than P. lateralis (<26oC).
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Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
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