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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 bilorbang S. Aghighi & T. I. Burgess was recovered from damp regions along the banks of two rivers in Western Australia. It is a clade 6 species that has identical ITS sequences as the provisional species P. taxon oaksoil but differs from this taxon in that it is homothallic rather than sterile. Associated with declining Rubus anglocandicans along river banks in Western Australia.
1. Sporangia
Sporangia abundant in liquid cultures and also in V8 agar, persistent, terminal, nonpapillate, limoniform (Fig. 1a), limoniform with a tapering base, ellipsoid (Fig. 1b), ovoid (Fig. 1c) and less frequently obpyriform (Fig. 1d), peanut shaped (Fig. 1e) and club shaped (Fig. 1f), average size 51.6 ± 6.4×29.0 ± 4.6 μm with a length/ breadth ratio 1.8 ± 0.3 μm. Conspicuous basal plug common. Sporangiophores simple, sometimes with basal swelling or swelling along the sporangiophore. Sporangial proliferation external and internal observed both in liquid culture and V8 agar (Fig. 1g-h). Direct germination of sporangia and germination of zoospores inside sporangia were observed on agar media. Zoospores were discharged through exit pores 10.4–13.4 μm wide (av. 11.6 ± 2.5 μm). They were limoniform, ovoid to reniform whilst motile, becoming spherical (av. diameter 10.9 ± 1.7 μm) on encystment. Cysts often germinated with up to three hyphae. Hyphal swellings globose to ellipsoid, catenulate or angular with radiating hyphae with a mean diameter of 18.6 ± 4.8 μm (Fig. 1i).
2. Chlamydospores
Chlamydospore not formed.
3. Sex Organs
Homothallic, with oogonia globose and averaged 33.5 ± 4.4 μm. Oospores highly plerotic to slightly aplerotic, averaged 31.3 ± 4.1 μm (Fig. 2a-b). Most oogonia contained oospores with a large ooplast or with two ooplasts (Fig. 3c) and multiple nuclei (Fig. 2d). Oospore wall, thick with a mean of 3.0 ± 08 μm. Antheridia paragynous and globose to cylindrical (12.4 ± 2.9× 14.1 ± 2.9 μm) and up to six finger- like projections were observed (Fig. 2e-f).
4. Growth Temperatures
Optimum temperature on V8 agar 25 °C, average radial growth rate 4.2 ± 0.1, maximum temperature 32.5 °C with limited growth at 4° C.
5. Growth Characteristics in Culture
Colony in V8 agar stellate to petaloid (carnation shape) Fig. 3a) colonies with sparse to limited aerial mycelium on carrot agar (Fig. 3b) and malt extract agar (Fig. 3c) and petaloid, dense-felty and dome shape at the centre on half-strength PDA (Fig. 3d).
6. Distinguishing Characteristics
P. bilorbang most closely resembles other homothallic species in Clade 6; P. gregata, P. gibbosa and P. megasperma, but can be easily distinguished based on a combination of molecular and morphological differences. All four species have been isolated from soil in Western Australia; P. gregata and P. gibbosa are only known from WA, while P. megasperma and P. bilorbang have been isolated elsewhere. In comparison to these species, P. bilorbang has the ability to produce chains of nested and extended proliferating sporangia, external proliferation, production of secondary lateral sporangia and forming branched sporangiophores in primary sporangia. P. bilorbang produces smooth-walled oogonia, whilst P. gibbosa forms ornamented oogonia. Moreover, P. bilorbang has the ability to form aggregations on agar media but P. gibbosa and P. megasperma do not. Additionally, zoospores of P. bilorbang can germinate with up to three germ tubes. In comparison with P. gregata, P. gibbosa and P. megasperma, P. bilorbang grows very slowly on PDA and moderately slowly on other media, and unlike these species it produces stellate colonies on carrot and V8A.
7. Type isolate
AUSTRALIA, Western Australia, Pemberton, banks of the Warren River, from rhizosphere soil of dying Rubus anglocandicans, 2010, collected by S. Aghighi, holotypus MURU 470; cultures ex-type CBS 131653; ITS, coxI, HSP90, BT and NADH sequence JQ256377, JQ256375, JQ256376, JQ256374 and JQ256378, respectively.: MycoBank MB563863.
Has been reported to be pathogenic on Rubus anglocandicans
Aghighi, S., St. J. Hardy, G. E., Scott, J. K., Burgess, T. I. 2012. Phytophthora bilorbang sp. nov., a new species associated with the decline of Rubus anglocandicans (European blackberry) in Western Australia. Eur. J. Plant Pathol. 133:841-855.
This species page was adapted from Aghighi et al. (2012). The comments of Treena Burgess, Centre for Phytophthora Science and Management, Murdoch University, Australia, on the content of this page and providing images is gratefully acknowledged.
Isolate list