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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 pistaciae Mirab. 2001 (Oomycetes, Pythiales)
Distribution: Asia (Iran, type).
Substrate: Roots, crown, soil.
Disease Note: Associated with gummosis.
Host: Pistacia vera (pistachio, Anacardiaceae).
Supporting Literature:
Mirabolfathy, M., Cooke, D.E.L., Duncan, J.M., Williams, N.A., Ershad, D., and Alizadeh, A. 2001. Phytophthora pistaciae sp. nov. and P. melonis: the principal causes of pistachio gummosis in Iran. Mycol. Res. 105: 1166-1175
Updated on Jun 27, 2006
Phytophthora pistaciae Mirabolfathy was initially classified as a P. megasperma like species that was recovered from diseased Pistacia vera. Subsequent analysis led to its description as P. pistaciae. In phylogenetic analysis it is in clade 7b related to P. melonis (Mirabolfathy et al. 2001).
1. Sporangia
Sporangiophores simple and unbranched. Sporangia not produced on solid media but formed in liquid culture, terminal with internal proliferation (` nesting '), persistent, nonpapillate, on average 62¬38 µm (38-98 x 28-50 µm) with a length:breadth ratio approximately 1.6, ellipsoid, ovoid, obpyriform, always germinating indirectly as zoospores through a broad apical pore.
2. Chlamydospores
No chlamydospores.
3. Sex Organs
Homothallic, oogonia and oospores abundant in the roots of Pistacia vera and in single culture in V8A. Oogonia not ornamented in culture, 35 µm average diameter (range 25-44 µm), wall 1.4 µm thick, colored in older cultures. Oospores aplerotic, spherical, not colored, 27 µm av. diameter (21-33 µm), wall 1.5-2.5 µm thick. Antheridia paragynous, rarely amphigynous, regularly spherical, ovoid ellipsoid in shape, 15¬14 µm (8-20 x 8-18 µm).
4. Growth Temperatures
Growth on SAMA between 5-35° C with optimum at 30° C (rate of growthC3 mm/d).
5. Growth Characteristics in Culture
Colonies uniform in appearance on all agars but mycelium fluffy on V8A and a nutrient-defined agar (SAMA), appressed on malt extract agar (MEA), and sparse on cornmeal agar (CMA). Hyphae hyaline, normally nonseptate but a few septa when old, 2-7 µm wide (av. 4.8 µm) with occasional swellings.
6. Distinguishing Characteristics
Phytophthora pistaciae has smaller oospores than P. megasperma s.s.
Isolated from the roots, crowns and soil surrounding Pistacia vera affected by gummosis.
Mirabolfathy, M., Cooke, D. E. L., Duncan, J. M., Williams, N. A., Ershad, D. And Alizadeh, A. 2001. Phytophthora pistaciae sp. nov. and P. melonis: the principal causes of pistachio gummosis in Iran Mycol. Res. 105: 1166-1175
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS. This species page was adapted from Mirabolfathy et al. (2001).
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