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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 capensis C.M. Bezuidenhout, Denman, A. McLeod & S.A. Kirk 2010 (Oomycetes, Pythiales)
Distribution: South Africa.
Host: Various hosts.
Supporting Literature:
Bezuidenhout, C.M., Denman, S., Kirk, S.A., Botha, W.J., Mostert, L., and McLeod, A. 2010. Phytophthora taxa associated with cultivated Agathosma, with emphasis on the P. citricola complex and P. capensis sp. nov. Persoonia 25: 32-49.
Updated on Mar 07, 2011
Phytophthora capensis C.M. Bezuidenhout, Denman,A. McLeod & S.A. Kirk was recovered from diseased Agathosma spp. in South Africa and historically was part of the P. citricola species complex. Recent reanalysis has classified it as a new species that in phylogenetic analysis it is in clade 2 closely related to P. citricola s. s., P. multivora and P. plurivora (Bezuidenhout et al. 2010).
1. Sporangia
Sporangia are semipapillate, non-caducous, non-proliferating and single, formed on the terminal ends of sporangiophores. There is a high degree in uniformity of shape: limoniform, occasionally ovoid and they are single lobed. They are attached centrally with no basal plug and only small to moderate numbers of sporangia are formed in pond water. The size of sporangia is variable ranging in length from 27.5–50 μm (av. 39.1 μm; SD 6 μm) and in width from 17.5–32.5 μm (av. 24 μm; SD 3.3 μm). The length : breadth ratio is 1.6–1.7, exit pore width ranges from 5–(5.5)–7.5 μm and the diameter of encysted zoospores is 10–(12.7)–15 μm.
2. Chlamydospores
No chlamydospores or hypal swellings observed.
3. Sex Organs
It is homothallic, forming numerous oospores after 8 d when incubated in the dark on CA at temperatures ranging from 15–22.5 °C. The number of oospores produced in culture decline sharply at temperatures above 22.5 °C and ceased at 27.5 °C. Antheridia are paragynous, diclinous in origin, single celled and more or less square ranging from 5–12.5 μm (mean L × B 9.0–9.1 μm; SD L×B 1.8 × 1.7 μm). Oogonia are round, the diameter ranges from 20–27.5 μm (mean 24 μm, SD 2.5 μm) and they are formed on the terminal ends of hyphae. Oospores are plerotic and thick-walled (> 2.5 μm (mean 2.7 μm). The average oospore diameter is 22.7 μm (SD 2 μm) covering a range between 20–27.5 μm, and > 90 % of oospores reach maturity.
4. Growth Temperatures
Cardinal temperatures: minimum 5 °C, optimum 22.5 °C, maximum 27.5 °C and lethal temperature 30 °C. Daily growth rate at 20 °C was 6.6 mm per day.
5. Growth Characteristics in Culture
Phytophthora capensis has a distinctive uniform, chrysanthemum- pattern colony morphology on carrot agar (CA) and forms abundant aerial mycelium after four days at temperatures between 15–27.5 °C. The mycelium is hyaline, with a low level of branching (similar to that of P. cactorum) and on average hyphal diameter is 6 μm.
6. Distinguishing Characteristics
Sporangia formed by all taxa in the P. citricola complex are semi-papillate. Sporangia of P. capensis are remarkable in that they are very uniform in shape although variable in size. They also have the smallest dimensions of all species in the P. citricola complex.
The growth of P. capensis was fast and comparable to P. citricola clade E sensu Jung & Burgess (2009). However, P. capensis had an optimal growth temperature of 22.5 °C as opposed to 25 °C for P. citricola clade E. Furthermore, at temperatures above 22.5 °C, the growth of P. capensis tailed off in comparison to P. citricola clade E. The lethal temperature for P. capensis was 30 °C, but was 35 °C for P. citricola clade E.
The morphology of P. capensis was striking by having abundant aerial mycelium forming a clear chrysanthemum pattern. A similar morphology was evident in P. citricola s.str. with the notable difference of colonies having little aerial mycelium. The chrysanthemum pattern was formed by mycelium mostly submerged in agar. Phytophthora citricola clade E sensu Jung & Burgess (2009) also had similar colony morphology to the above but the chrysanthemum pattern only formed close to the inoculum plug and changed to a radially-striate pattern as the colony advanced to the margin of the Petri dish
P. capensis is associated with Agathosma spp. and has not been evaluated for pathogenicity towards this host.
Bezuidenhout, C. M., Denman, S., Kirk, S. A., Botha, W.J., Mostert, L., McLeod, A. 2010. Phytophthora taxa associated with cultivated Agathosma, with emphasis on the P. citricola complex and P. capensis sp. nov. Persoonia 25: 32– 49.
Jung T, Burgess TI. 2009. Re-evaluation of Phytophthora citricola isolates from multiple woody hosts in Europe and North America reveals a new species, Phytophthora plurivora sp. nov. Persoonia 22: 95–110.
This species page was adapted from Bezuidenhout et al. (2010). Comments on the content of this page by Dr. A. McLeod are gratefully acknowledged.
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