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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 botryosa Chee 1969 (Oomycetes, Pythiales)
Notes: According to Kroon et al. (2004), the status of P. botryosa is unclear; it is closely related to P. palmivora based on molecular analysis.
Distribution: Asia (Malaysia, Thailand, Andaman Islands, Vietnam).
Substrate: Leaves, seed pods.
Disease Note: Leaf fall, pod rot, and black stripe of rubber (Stamps 1985).
Host: Hevea spp. (Euphorbiaceae). Theobroma cacao and other cultivated spp. can be infected on inoculation (Stamps 1985).
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.
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
Stamps, D.J. 1985. Phytophthora botryosa. C.M.I. Descript. Pathog. Fungi Bact. 835: 1-2
Updated on Jun 02, 2006
P. botryosa is classified in group II (Stamps et al. 1990). Morphology is described by Waterhouse (1974c) and Stamps (1985e). See Tables 4.2 and 4.3 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for tabular keys. The following description is from Chee (1969a). Morphology is shown in Figure 1. See also Tables 51A.4 and 51A.5 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for morphological comparisons with P. palmivora and related species.
1. Sporangia
Sporangia form in yellowish clumps (average about 90 sporangia per clump) and are inconspicuously papillate and oval or occasionally ovoid (28 x 15 µm) (Stamps 1985e); the length-breadth ratio varies from 1.6 to 2.1. See Table 4.2 in Erwin and Ribeiro (1996, Phytophthora Diseases Worldwide) for measurements by Chee (1969a). Sporangia are caducous with pedicels 5 to 20 µm long and are produced on sympodially branched sporangiophores with nodal swellings. Sporangia form as yellowish clumps on lima bean agar when incubated under light.
2. Chlamydospores
Chlamydospores are rare but when formed are terminal; diameters range from 14 to 30 µm (average 18.7 µm) (Chee 1969a).
3. Sex Organs
P. botryosa is heterothallic and produces oospores when A1 and A2 mating types are paired. Chee (1969a) reported that one-third of the isolates produced a few oospores in single culture (homothallic). Oospores have been found in pods of the rubber tree. Antheridia are amphigynous (14 13 µm); spherical oogonia are 25 to 30 µm in diameter, averaging 25 µm, and contain plerotic oospores that are 22 to 24 µm in diameter (Chee 1969a; Stamps 1985e).
4. Growth Temperatures
The minimum temperature for growth is 9oC, optimum 26oC, and maximum 32oC (Chee 1969a; Stamps 1985e).
5. Distinguishing Characteristics
P. botryosa differs from P. palmivora by its slower growth with little aerial mycelium on lima bean agar and its infrequent production of chlamydospores, which are smaller (Chee 1969a; Waterhouse 1974c) (Figure 1). P. botryosa closely resembles P. meadii, but it can be distinguished from P. meadii by its production of smaller sporangia with medium-length pedicels produced in conspicuous clumps. Oudemans and Coffey (1991c) stated that distinction between these species by sporangial morphology was problematic, although sporangia of P. botryosa were consistently smaller; however, isozyme patterns of P. meadii and P. botryosa showed a high level of genetic similarity. Both species were distinct from P. palmivora. P. botryosa was compared with isolates of several other species of rubber by Liyanage and Wheeler (1989a). Rose bengal (3 mg/liter) and streptomycin hydrochloride (5 mg/liter) in malt extract agar inhibited growth of P. palmivora but not of P. botryosa (Chee 1969a).
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
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