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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 inundata Brasier, Sánch. Hern. & S.A. Kirk 2003 (Oomycetes, Pythiales)
Distribution: Europe (France, Denmark, Spain, UK), South America (Brasier et al. 2003).
Substrate: Roots, collars. Also debris, water.
Disease Note: Root and collar rot.
Host: Plants in multiple families, including Aesculus hippocastanum (chestnut, Sapindaceae), Salix (willow, Salicaceae), Olea (olive, Oleaceae) and Vitis (grapevine, Vitaceae).
Supporting Literature:
Brasier, C.M., Sanchez-Hernandez, E., and Kirk, S.A. 2003. Phytophthora inundata sp. nov., a part heterothallic pathogen of trees and shrubs in wet or flooded soils. Mycol. Res. 107: 477-484
Updated on Jun 26, 2006
Phytophthora inundata Brasier, Sanchez-Hernandez & S. A. Kirk was initially described as the provisional species Phytophthora sp. O-group. It falls in clade 6, its next nearest known relative is P. humicola.
1. Sporangia
Sporangia produced on solid media such as CA irrigated with Petri’s solution, soil leachate or pond water; and in liquid media such as pea broth after repeated washing of mycelium. Sporangiophores single or sympodial, common range 150–850 µm. Sporangia terminal, persistent, non-papillate, ovoid or ovoidobpyriform; internally proliferating, average length 64.5 ± 10.7 X 47.7 ± 10.0 µm; range of means 54.7–85.6 X 40.0–66.5 µm; length:breadth ratio, range of means 1.2–1.5.
2. Chlamydospores
No chlamydospores or unusual swellings seen on CA.
3. Sex Organs
Isolates usually self sterile on CA. Some regularly A1 or A2 heterothallic, mating freely with other P. inundata isolates of the ‘opposite ’ sexual compatibility type. Others only weakly heterothallic, producing oogonia sporadically or unpredictably in pairings with sexually compatible P. inundata isolates, but still act as ‘ silent ’ A1 or A2 compatibility types, able to induce oogonial formation in A1s or A2s of other species such as P. drechsleri. Some P. inundata A1 or A2 isolates may exhibit sporadic self-fertility. Oogonia are smooth, subspherical. Oogonial diameter average 40.1 ± 3.5 µm (SD), range of means 34.7–43.4 µm. Antheridia single, amphigynous or predominantly so. Antheridia average length 16.5 ± 1.2 µm, range of means 15.1–18.4 µm; average width 15.9 ± 0.5 µm, range of means 15.5–16.5 µm. Oospores thick-walled, often yellowish, smooth, subspherical, aplerotic with an average diameter of 35.7 ± 2.8 µm, range of means 31.4– 38.2 µm. Oospore wall thickness average 5.4 ± 0.9, range of means 4.9–7.2 µm.
4. Growth Temperatures
Optimum temperature for growth on CA, ca 28–30° C. Radial growth on CA at 28–30° C, ca 6–8 mm day. Upper temperature limit for growth on CA, ca 35–37° C.
5. Growth Characteristics in Culture
Colonies on CA with irregular, stellate to broad lobed patterns.
6. Distinguishing Characteristics
P. inundata can be distinguished from other clade 6 taxa and similar non-papillate species in other clades such as P. cinnamomi or P. cryptogea, on a combination of its relatively characteristic colony type on CA, its fast growth rate at 28–30° C, its high upper temperature limit for growth of 35–37° C, its normal or partial A1 X A2 sexual incompatibility system, its relatively large oogonia with thick-walled oospores and its unique ITS sequence. For accurate identification, a test of growth rate at 28–30° C, of upper temperature limit for growth and an analysis of the ITS sequence is recommended.
Associated with root and collar rots of hardwood trees and shrubs, including Aesculus, Olea, Salix, Prunus, and Vitis, especially after flooding or on very wet soils. Also found on debris and in water in rivers and ponds. Present known distribution: northern Europe (UK, France, Denmark), southern Europe (Spain and Italy) and South America.
Brasier, C. M., Sanchez-Hernandez, E. and Kirk, S. A. 2003. Phytophthora inundata sp. nov., a part heterothallic pathogen of trees and shrubs in wet or flooded soils. Mycol. Res. 107: 477–484
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS. This species page was adapted from Brasier et al. (2003)
Isolate list