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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 tropicalis Aragaki & J.Y. Uchida 2001 (Oomycetes, Pythiales)
Notes: Phytophthora palmivora (as P. palmivora MF4) is considered by some authors to be a partial synonym (e.g., Aragaki & Uchida 2001). Various taxonomists including Mchau et al. (1995) have broadened the species concept of Phytophthora capsici to include a range of morphological characters and the two isozyme groups CapA or Cap 1, including -Phytophthora palmivora MF4-) and CapB or Cap 2. Aragaki & Uchida (2001) argued for a narrower species concept, referring several tropical isolates (= Cap A or Cap 1) to the new species Phytophthora tropicalis. Mchau & Coffey (1995) listed Phytophthora mexicana as a possible synonym of Phytophthora tropicalis (as Phytophthora capsici type CapA).
Distribution: Pacific Islands (USA: HI); also reported from North America (USA: VA) and Europe (the Netherlands). This species may have been reported before 2001 as Phytophthora capsici; therefore, the full geographic distribution is unclear.
Host: 14 genera in 12 families.
Supporting Literature:
Aragaki, M., and Uchida, J.Y. 2001. Morphological distinctions between Phytophthora capsici and P. tropicalis sp. nov. Mycologia 93: 137-145
Mchau, G.R.A., and Coffey, M.D. 1995. Evidence for the existence of two subpopulations in Phytophthora capsici and a redescription of the species. Mycol. Res. 99: 89-102
Updated on Jun 05, 2006
Phytophthora tropicalis Aragaki et J. Y. Uchida was initially classified as P. capsici but was separated into a distinct species by Aragaki and Uchida (2001) based on morphological differences. Differences in isozyme profiles between these two species were reported previously (Machu and Coffey, 1995; Oudemans and Coffey, 1991).
1. Sporangia
Sporangia form singly or on monochasial sympodia on solid medium under continuous light at 24° C. Caducous with a pedicel usually longer than 50 µm (Fig. 1). Sporangia have conspicuous papillae, usually single but occasionally isolates may have multiple. Sporangia shapes are uniform, oboviod, pyriform or ellipsoidal with tapered bases. Mostly radially symmetrical but bilateral symmetry can be common in some isolates. Range in size form 19-27 µm in diameter, 40-55 µm long with a length:breadth ratio of 1.8 - 2.4.
2. Chlamydospores
Many, but not all isolates produced chlamydospores in culture ranging between 27.6 and 33.9 µm in diameter with walls up to 3 µm thick.
3. Sex Organs
Heterothallic but many isolates appear to be sexually sterile. Oogonia are spherical, brown to reddish-brown on RMA, smooth walled averaging 28 µm in diameter (Fig. 2). Amphigynous antheridia, broadly cylindrical or barrel shaped 13.0 x 14.8 µm. Spherical oospores, hyaline, plerotic and thick walled.
4. Growth Temperatures
Minimum below 10° C, optimum 24-28° C and maximum 35° C. Most isolates grow poorly or not at all at 35° C.
5. Growth Characteristics in Culture
Colonies mostly appressed with radiating strands and sparse aerial hyphae on carrot agar at 24-28° C. Hyphae 3-8 µm diameter
6. Distinguishing Characteristics
P. tropicalis can be differentiated from P. capsici by its narrow deciduous sporangia less than 26 µm in diameter, predominantly tapered sporangia base, production of chlamydospores by most isolates, poor or no growth at 35° C and weak or no virulence to Capsicum.
7. Type isolate
Holotype CBS 434.91 recovered from M. integrifolia in Hawaii (isolate H245 of M. Aragaki).
Generally avirulent on Capsicum annuum (some isolates may be very weakly virulent). Has been reported from Macadamia integrifolia, Theobroma cacao Anthurium andraeanum, Radermachera sinica, Solanum melongena, Dianthus caryophyllus, Hedera helix, Annona cherimola, Sechium edule, and Leucospermum sp .
Aragaki, M. and Uchida, J. Y. 2001. Morphological distinctions between Phytophthora capsici and P. tropicalis sp. nov. Mycologia 93:137-145.
Machu, G. R. A. and Coffey, M. D. 1995. Evidence for the existence of two subpopulations in Phytophthora capsici and a redescription of the species. Mycol. Res. 99:89-102.
Oudemans, P. and Coffey, M. D. 1991. A revised systematics of twelve papillate Phytophthora species based on isozyme analysis . Mycol. Res. 95:1024-1046.
This species page was adapted from Aragaki and Uchida (2001). Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
Isolate list