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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 brassicae De Cock & Man in 't Veld 2002 (Oomycetes, Pythiales)
Notes: Previously considered to be Phytophthora porri; may be reported as P. porri in literature before 2002.
Distribution: Europe (UK, Germany); North America (USA: WI).
Substrate: Leaves?
Disease Note: Storage rot (see Erwin & Ribeiro as P. porri).
Host: Brassica oleracea and Brassica sinensis (Brassicaceae).
Supporting Literature:
Man in 't Veld, W.A., de Cock, A.W.A.M., Ilieva, E. , and Levesque, C.A. 2002. Gene flow analysis of Phytophthora porri reveals a new species: Phytophthora brassicae sp. nov. Eur. J. Pl. Pathol. 108: 51-62
Updated on Jun 07, 2006
Phytophthora brassicae De Cock and Man in ’t Veld was initially described as P. porri but based on morphological features and results of molecular analysis it has been redescribed as a new species. Phylogenetically it is in clade 8b basal to P. porri and P. primulae.
1. Sporangia
Sporangia abundantly produced in and on cornmeal agar as well as on hemp seeds in soil extract, developing singly or in sympodia, terminally, occasionally laterally attached or intercalary, globose to ovoid, sometimes distorted, with broad and indistinct papilla (in some other isolates none), without or with weak apical thickening, 25–48 × 40–74 μm, length to width ratio 1.4 (in other isolates 1.3–1.5). Part of the sporangia caducous, easily seceding upon preparation, with a short pedicel, consisting of a plug in the subtending hyphae. Zoospores developed below 20° C.
2. Chlamydospores
3. Sex Organs
Oogonia developed on cornmeal agar and V8 agar, only during a short period after isolation, only occasionally later, terminal, mostly on short side branches, globose including a part of the subtending hypha, 30–41 μm diameter (in some other isolates up to 65 μm); wall smooth, inner side of the wall undulate, colorless to pale yellow, up to 2 μm thick (in some other isolates also dark yellow and up to 6 μm thick). Antheridia 1–2 per oogonium, terminal, diclinous, mostly amphigynous, occasionally paragynous, variable in shape, 16–20 μm diam. Oospores aplerotic, wall up to 2 μm thick.
4. Growth Temperatures
Cardinal temperatures for growth: minimum below 3° C, optimum 21° C, maximum 27° C. Daily radial growth on cornmeal agar at optimum temperature 6.4 mm, at 24° C 2.3 mm.
5. Growth Characteristics in Culture
Colonies on cornmeal agar submerged or with some low aerial mycelium, no distinct growth pattern; on V8 with low aerial mycelium and powdery appearance. Main hyphae up to 7 μm wide, often coiled. Hyphal swellings present in hemp-seed/water cultures, intercalary, often in chains and/or provided with radiating hyphae, occasionally terminal, (sub-)globose, 10–40(–53) μm diam.
6. Distinguishing Characteristics
Phytophthora brassicae is characterized by low cardinal temperatures for growth, coiled hyphae, and semi- to non-papillate sporangia. It is morphologically similar to and closely related with P. porri, but can be distinguished by the abundant sporangium production on agar, the appressed aerial mycelium on V8, and rapid decrease of oogonium production after isolation.
Other Phytophthora species with semi-papillate sporangia and low cardinal temperatures are P. infestans, P. mirabilis, P. phaseoli, P. hibernalis, P. ilicis, P. primulae, and P. syringae. The former three, P. infestans, P. mirabilis, and P. phaseoli differ from P. brassicae by producing compound sympodial sporangiophores with basal swellings and no hyphal swellings or chlamydospores; in addition to the morphological differences, restriction patterns of mitochondrial DNA of these species are quite different from those of P. brassicae. P. hibernalis differs by its characteristic obovoid sporangia, which are caducous with a long pedicel; P. ilicis by its small, caducous sporangia with medium length pedicel, abundant oogonia, absence of hyphal swellings and chlamydospores and very slow growth. P. primulae differs by often distorted sporangia, frequent oogonium production and paragynous antheridia; P. syringae by small chlamydospores and small, paragynous antheridia with tangled hyphae below.
Causing brown rot in stored cabbages.
Man in ’t Veld, W. A., de Cock, A. W. A. M., Ilieva, E. and Lévesque, C. A. 2002. Gene flow analysis of Phytophthora porri reveals a new species: Phytophthora brassicae sp. nov. European Journal of Plant Pathology 108: 51–62.
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
This species page was adapted from Man in ’t Veld et al. (2002).
Isolate list