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 Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).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 thermophila T. Jung, M.J.C. Stukely & T.I. Burgess 2011 (Oomycetes, Pythiales)
Distribution: Australia.
Substrate: Soil associated with dying plants.
Supporting Literature:
Jung, T., Stukely, M.J.C., Hardy, G.E.St.J., White, D., and 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.
Updated on Aug 26, 2011
During surveys of dying vegetation in natural ecosystems and associated waterways in Australia (Western Australia, Victoria, Tasmania) many new taxa have been identified from Phytophthora ITS Clade 6. Among these is P. thermophila, a species which is common in waterways and causes scattered mortality within native vegetation.
1. Sporangia
Sporangia are rarely observed on solid agar but are produced abundantly in non-sterile soil extract. Sporangia are borne terminally on unbranched sporangiophores, often in chains of internally proliferating sporangia. Due to the lack of external proliferation, no sympodia are formed. Sporangia are non-caducous and nonpapillate. Sporangial shapes range from ovoid (Fig. 1a) and elongated ovoid to limoniform, ellipsoid (Fig. 1c) and, less frequently, pyriform, obpyriform or cylindrical. Features such as a tapering base or a conspicuous basal plug are quite common. Sporangia usually proliferate internally in both a nested and extended way (Fig. 1b, d). External proliferation is never observed. Sporangial dimensions average 44.8 ± 6.3 x 25.7 ± 3.9 µm (overall range 29.0 – 64.8 x 15.6 – 39.3 µm). The length/breadth ratio of the sporangia average 1.78 ± 0.26.
2. Chlamydospores
Hyphal swellings have a mean diameter of 12.6 ± 2.3 µm (Fig. 2a). Globose, intercalary or terminal chlamydospores with a mean diameter of 41.5 ± 14.7 µm are produced in liquid culture (Fig. 2b). Some isolates produced small hyphal aggregations (Fig. 2c).
3. Sex Organs
P. thermophila is sterile or inconsistently silent homothallic. It does not produce gametangia in single culture or when paired with other P. thermophila isolates, A1 and A2 tester strains of P. cryptogea, P. cambivora and P. cinnamomi, or with T. reesei. Also, none of the isolates stimulate the formation of oogonia in the A1 or A2 tester strains. Interestingly, one isolate formed abundant oogonia in single culture when flooded with non-sterile soil filtrate (Fig. 2d).
4. Growth Temperatures
P. thermophila grows on V8 agar (V8A) at 5-35°C with an optimum near 33°C (radial growth rate 4.8 ± 0.6 mm d-1). No growth occurred at 37°C, but one isolate resumed growth when plates incubated for 7 d at 37°C were transferred to 20°C
5. Growth Characteristics in Culture
On V8A (Fig. 3a), carrot agar (Fig. 3b) and MEA (Fig. 3c) P. thermophila forms stellate to petaloid colonies. Colonies on PDA are irregular and dense-felty (Fig. 3d).
6. Distinguishing Characteristics
Phytophthora thermophila has previously been misidentified as P. drechsleri and is referred to as P.sp.3 (Burgess et al. 2009). This species can be distinguished from P. drechsleri mainly by being either sterile or silently homothallic with paragynous antheridia, but also by the branching of internally proliferating sporangiophores outside the empty primary sporangium and the regular occurrence of diplanetism; from P. gonapodyides by its markedly higher optimum temperature for growth, a higher length/breadth ratio of the sporangia, the absence of external sporangial proliferation, the frequent production of hyphal swellings which were often catenulate and sometimes had radiating hyphae, the occurrence of chlamydospores in some isolates, and the inability to induce selfing in A2 isolates; from P. megasperma by the sterility of most isolates, the production of chlamydospores by some isolates, and a markedly higher optimum and a slightly higher maximum temperature for growth.
7. Type isolate
AUSTRALIA, WESTERN AUSTRALIA, Dwellingup, from rhizosphere soil of declining Eucalyptus marginata, 2004, holotype MURU 464 (dried culture on V8A, Herbarium of Murdoch University, Western Australia), culture ex-type VHS13530, CBS127954. cultures ex-type CBS127951 and VHS21998; ITS, ß-tubulin, HSP90, cox1 and NADH, and sequence GenBank HQ012958, JN547613, HQ012916, HQ012872 and JN547700 respectively MycoBank MB518766
Recovered from water, rhizosphere soil associated with dying plants (Eucalyptus marginata, Banksia grandis).
Known Diagnostics - Commonly detected by baiting of stream water and rhizosphere soil and plating on PARPNH selective medium. Also isolated when filtering stream water
Burgess TI, Webster JL, Ciampini JA, White D, Hardy GESJ, Stukely MJC. 2009. Re-evaluation of Phytophthora species isolated during 30 years of vegetation health surveys in Western Australia using molecular techniques. Plant Disease 93: 215-223.
Jung T, Stukely MJC, Hardy GES, White D, Paap T, Dunstan WA, Burgess TI. 2011. Multiple new Phytophthora species from ITS clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications. Persoonia 26: 13-39.
This page was written by Treena Burgess, Centre for Phytophthora Science and Management, Murdoch University, Australia.
Isolate list