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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).
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Phylogenetically, P. amnicola T.I. Burgess & T. Jung resides in a strongly supported terminal clade in clade 6 and shares a common ancestor with P. fluvialis, P. litoralis, and P. thermophila (Crous et al. 2011a, Jung et al. 2011). In a multigene phylogeny of the ITS, HSP90, beta tubulin, NADH, and cox1 gene regions, P. amnicola differs from P. fluvialis by 144 steps (3.1 %), P. litoralis by 158 steps (3.4 %), and P. thermophila by 121 steps (2.6 %). P. amnicola has two ITS alleles, one of which contains a 3bp indel; consequently the ITS region cannot be sequenced without cloning. These four species have all been isolated from waterways in the south-west of Western Australia. Phytophthora amnicola has a life strategy similar to P. litoralis and P. fluvialis, being sterile and having abundant and continuous asexual multiplication in water courses via chains of nested and extended proliferating sporangia, external proliferation, and the production of secondary lateral sporangia. Isolated only from water in Western Australia.
1. Sporangia
Sporangia produced abundantly in non-sterile soil extract, noncaducous, non-papillate, frequently ovoid (Fig. 1b) to limoniform (Fig. 1a) or rarely ellipsoid, obpyriform or pyriform, often with a long tapering base; 62 ± 9.0 × 35.3 ± 5.6 μm (overall range 39–78 × 17–43 μm), length/breadth ratio 1.8 ± 0.2. Sporangial proliferation in chains of internally proliferating sporangia in both a nested and extended way (Fig. 1c-d). Internally proliferating sporangiophores, sometimes branching inside or just outside the empty sporangium. Ellipsoid to irregular, catenulate hyphal swellings in clusters (14.2 ± 4.0 μm) (Fig. 1d)
2. Chlamydospores
Chlamydospores not observed.
3. Sex Organs
Gametangia not produced in single culture or when paired with A1 and A2 tester strains of P. cinnamomi.
4. Growth Temperatures
Radial growth rates on V8 agar at optimum temperature (25–32.5 °C) and near the maximum temperature (37.5 °C) 6.4 ± 0.4 mm/d and 0.3 ± 0.07 mm/d, respectively.
5. Growth Characteristics in Culture
Club-shaped, knotty lateral hyphae formed in water. Colonies are stellate with limited aerial mycelium on V8 agar (Fig. 2a); rosaceous on carrot agar (Fig. 2b) and growth on potato-dextrose agar is very slow (Fig. 2c).
6. Distinguishing Characteristics
The species can be separated by its overall larger sporangia and its broad optimum for growth (25–32.5 °C) as opposed to a peak at 32.5 °C for the other species. As with P. thermophila and P. litoralis, P. amnicola grows very slowly on PDA, but unlike these species it produces rosaceous colonies on carrot agar.
7. Type isolate
AUSTRALIA, Western Australia, Perth, Poison Gully Creek, baited from still water, Dec. 2009, D. Hüberli, holotype MURU 471; cultures ex-type CBS131652 = DH228, ITS, ß-tubulin, HSP90, cox1, NADH, and LSU sequence GenBank JQ029956, JQ029952, JQ029944, JQ029948, JQ029940, and JX069838 respectively, MycoBank MB563849.
Burgess, T. I., Huberli, D., St. Hardy, G. E., Stukely, M. J. C., Jung, T. 2012. Phytophthora amnicola. Persooni 28:140-141.
Jung, T., Stukely, M. J. C., St. Hardy, G. E., White, D., Paap, T., 2011. Multiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications. Persoonia 26: 13–39.
The contribution by Treena Burgess, Centre for Phytophthora Science and Management, Murdoch University, Australia, in contributing to this species page and providing images is gratefully acknowledged.
Isolate list