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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 himalsilva Vettraino, Brasier & Vannini was recovered from rhizosphere soil around Quercus, Castanopsis, Carpinus and Cupressus spp. growing in Western Nepal (the only location from which this species has been recovered). Phylogenetic analysis with the ITS, beta tubulin and cox1 places P. himalsilva in clade 2c closely affiliated with P. citrophthora.
1. Sporangia
Sporangia papillate, sometimes bipapillate, subterminal or lateral, variable in form, commonly elongate to obpyriform and limoniform; rarely dichotomously or even trichotomously branched. Sporangial lengths ranged from 32.5 to 87.5 µm (mean 64.5 ± 4.4 µm) with widths from 17.5 to 52.5 µm (mean 33.1 ± 2.0 µm) with significant differences observed among isolates. The overall mean length/breadth ratio was 1.95 ± 0.1. Sporangia partially caducous, with very variable unstructured ‘pedicels’ (sporangiophore segments) of mean length 15.1 ± 1.5 µm. Readily formed on cornmeal agar plugs irrigated with pond water or nonsterile soil leachate.
2. Chlamydospores
No chlamydospores observed.
3. Sex Organs
Species homothallic; oospores abundant in culture. Oogonia smooth walled, overall width mean 26.7 ± 0.9 µm (range of means 25.9-27.2 µm). Oospores aplerotic, spherical, 23.6 ± 0.6 µm (range of means 22.8-24.1 µm). Antheridia mostly rounded, either paragynous or amphigynous, rarely both.
4. Growth Temperatures
Optimal growth rate of individual isolates variable, lying between 20 and 27.5° C. The upper limit for growth on cornmeal agar ca. 30-31° C.
5. Growth Characteristics in Culture
On cornmeal agar produced a small amount of floccose aerial mycelium near the centre of the colony and stellate to chrysanthemumgrowth patterns in the bulk of the colony
6. Distinguishing Characteristics
Phytophthora himalsilva is most readily distinguished from the other four known species in Clade 2c by its homothallism, formation of paragynous antheridia, and cardinal temperatures for growth
P. himasilva has been recovered from the rhizosphere of Quercus, Castanopsis, Carpinus and Cupressus spp. in Nepal. In pathogenicity trials it was capable of causing lesions on twigs of Juglans regia.
Vettraino, A. M., Brasier, C. M., Brown, A. V., Vannini, A. 2011. Phytophthora himalsilva sp. nov. an unusually phenotypically variable species from a remote forest in Nepal. Fungal Biology 115:275-287.