Name and publication

Phytophthora gregata T. Jung, M.J.C. Stukely & T.I. Burgess (2011)

Jung T, Stukely MJC, Hardy GE StJ, White MD, Paap T, Dunstan WA, and Burgess TI. 2011. Multiple new Phytophthora species from ITS Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
6 associated with natural ecosystems in Australia: evolutionary and ecological implications. Persoonia 13: 13–39.

Nomenclature

from Jung et al. (2011)

Mycobank

MB518764

Synonyms: was referred to as P.sp.7 by Burgess et al. (2009) and as taxon raspberry by Brasier et al. (2003)

Etymology

refers to the abundant hyphal aggregations regularly formed by all isolates (gregata Latin = aggregated, in clumps)

Typification

Type: WESTERN AUSTRALIA, Busselton, from rhizosphere soil of dying Patersonia sp., 2009, VHS, holotype MURU 462 (dried culture on V8A, Herbarium of Murdoch University, Western Australia)

Ex-type: CBS 127952 and VHS 21962

Sequences for ex-type in original manuscript: CBS 127952 = ITS rDNA HQ012942, HSP90 HQ012904, cox1 HQ012858

Ex-type in other collections

(ET) CBS 127952, VHS21962, NRRL 640174,  WPC P19588, S&T BL 37 (Abad), 62B9 (Hong)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora gregata isolate CPHST BL 37 (= P19588) ITS rDNA MG865503, COI MH477746

Voucher sequences for Molecular Toolbox with seven genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1

(see Molecular protocols page) (In Progress)

Voucher sequences for Metabarcoding High-throughput Sequencing (HTS) Technologies [Molecular Operational Taxonomic Unit (MOTU)]

(see Molecular protocols page) (In Progress)

Sequences with multiple genes for ex-type in other sources

• NCBI: Phytophthora gregata CPHST BL 37
• NCBI Phytophthora gregata CBS 127952
• EPPO-Q-bank: Phytophthora gregata CBS 127952
• BOLDSYSTEMS: Phytophthora gregata (barcoding COI & ITS)

Position in multigenic phylogeny with 7 genes (ITS, β-tub, COI, EF1α, HSP90, L10, and YPT1)

Clade clade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
6b

Morphological identification

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology is faintly striate, stellate, or uniform on V8A, CA, MEA and PDA, but growth is denser on MEA and PDA. Minimum growth temperature 7.5°C, optimum 25°C, and maximum 32.5°C.

Conditions for growth and sporulation

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
 are produced in water cultures (soil extract or river water) and not observed in solid media. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are formed readily in single-strain culture on CA and V8A after about 10 d.

Asexual phase

SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
 are nonpapillatenonpapillate:
pertaining to the production of a non-distinct, or inconspicuous, papilla at the distal end of the sporangium (cf. papillate and semipapillate)
, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
, and usually ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
or limoniform in shape. SporangiaSporangia:
sac within which zoospores form, especially when water is cooled to about 10°C below ambient temperature; in solid substrates, sporangia usually germinate by germ tubes
average 51.0 ± 13.8 × 30.5 ± 5.9 μm (overall range 25.7–102.3 × 14.8–50.7 μm). Sporangiophores usually in simple sympodiasympodia:
a type of sporangiophore which appears simple, but where each successive sporangium develops on a branch behind and to one side of the previous apex, where growth has already ceased
and internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
, both nested and extended, occurs in chains. Hyphal swellings are abundant as were hyphal aggregations. ChlamydosporesChlamydospores:
an asexual spore with a thickened inner wall that is delimited from the mycelium by a septum; may be terminal or intercalary, and survives for long periods in soil
 absent.

Sexual phase

Homothallic. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
are globoseglobose:
having a rounded form resembling that of a sphere
, often with a tapering base, with smooth walls turning golden brown on maturity, average size 36.8 ± 4.1 mm (23.9–50.9 µm). OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
are apleroticaplerotic:
pertaining to a mature oospore that does not fill the oogonium; i.e. there is room left between the oospore wall and oogonium wall (cf. plerotic)
, globoseglobose:
having a rounded form resembling that of a sphere
, with a large ooplast and thick walls, average size 31.6 ± 4.0 µm (21.4–45.3). AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
 paragynous.

Most typical characters

Phytophthora gregata can be differentiated from other species from ITS Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
6 by the production of hyphal aggregates.

Specimen(s) evaluated

Australia, Western Australia, Busselton, from rhizosphere soil of dying Patersonia sp., 2009, VHS, CBS 127952 = VHS 21962; from dying Hakea sp. VHS 21961; Lancelin, from Xanthorrhoea preissii, 2001, VHS 9854; Byford, from native forest, 1995, DCE68; Scott River, 2009, VHS 21992; Cataby, from dying Banksia prionotes, 1996, HSA 2356; Nannup, from rhizosphere of Pinus radiata, 1981, MJS 235; MJS 238; Victoria, Toolangi State Forest, from rhizosphere of a Eucalyptus sp., 2008, MUCC 759; Devlins Bridge from pasture, 2008, MUCC 760

Additional isolates: CPHST BL 37 = P19588 WPC

Hosts and distribution

Distribution: Australia, North America (USA: OR)
Substrate: associated with roots of dying plants
Host: diverse hard and softwood posts

Retrieved January 30, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional info:
Distribution: Western Australia, Victoria
Substrate: roots, collars, and rhizosphere soil
Disease note: No pathogenicity trials have been conducted.
Hosts: rarely isolated in associated with other Phytophthora species in rhizosphere soil collected in wetter areas

Additional references and links

Burgess TI, Webster JL, Ciampini JA, White DW, 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.

Brasier CM, Cooke DEL, Duncan JM, Hansen EM. 2003. Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides – P. megasperma ITS Cladeclade:
a taxonomic group of organisms classified together on the basis of homologous features traced to a common ancestor
6, which tend to be high-temperature tolerant and either inbreeding or sterile. Mycological Research 107: 277–290.

 

• SMML USDA-ARS: Phytophthora gregata
• EPPO Global Database:  Phytophthora gregata 
• Forest Phytophthoras of the world: Phytophthora gregata
• CABI Digital Library: Phytophthora gregata
• Encyclopedia of Life (EOL): Phytophthora gregata
• Index Fungorum (IF): Phytophthora gregata

 

• Google All Phytophthora gregata
• Google Images Phytophthora gregata
• Google Scholar Phytophthora gregata

Fact sheet authors

Treena Burgess, Ph.D., Phytophthora Science and Management, Harry Butler Institute, Murdoch University, Australia

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Plant Pathogen Confirmatory Diagnostics Laboratory (PPCDL), United States of America.