Name and publication

Phytophthora elongata A. Rea, M. Stukely & T. Jung (2010)

Rea AJ, Jung T, Burgess TI, Stukely MJC, Giles E, and Hardy GE StJ. 2010. Phytophthora elongata sp. nov., a novel pathogen from the Eucalyptus marginata forest of Western Australia. Australas. Plant Path. 39: 477–491.

Corresponding author: tburgess@murdoch.edu.au

Nomenclature

from Rea et al. (2010)

Mycobank

MB515142

Synonymy

was referred to as P. sp.2 by Burgess et al. 2009

Etymology

refers to the occurrence of elongated sporangia

Typification

Type: WESTERN AUSTRALIA, Dwellingup, isolated from the rhizosphere of Eucalyptus marginata, April 2004, M. Stukely, MURU 453 dry culture in V8A agar preserved at Herbarium of Murdoch University, Western Australia

Ex-type: CBS 125799 (= VHS 13482)

Sequences for ex-type in original manuscript: Phytophthora elongata VHS 13482 = ITS rDNA GQ847754, CBS 125799 = COI: GQ847764 (deposited as COI but amplified with FM82, FM83 Martin and Tooley 2003, it should be called Cox1)

Ex-type in other collections

(ET) CBS 125799, NRRL 64165, VHS 13482,  WPC P19596, S&T BL 62 (Abad), 55C4 (Hong)

Molecular identification

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

Phytophthora elongata isolate CPHST BL 62 (= P19596 WPC) = ITS rDNA MG865485, COI MH136881

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 elongata CPHST BL 62 
• NCBI: Phytophthora elongata VHS 13482
• NCBI: Phytophthora elongata CBS 125799
• EPPO-Q-bank: Phytophthora elongata CBS 125799
• BOLDSYSTEMS: Phytophthora elongata (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
2e

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 petaloid on CA, V8A, MEA, and PDA. Minimum growth temperature 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 14 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 semipapillatesemipapillate:
pertaining to the production of shallow having papilla that are not well developed, shallow and less nipple-like than fully papillate structures
, persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
with varied shapes including markedly elongated. Normal 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 45.8 ± 6.3 x 28.4 ± 3.5 mm (overall range 26–76 x 19–42 µm), elongated 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 58.2 ± 12.7 mm x 24.5 ± 4.3 mm (overall range 34–90 x 16–40 µm). Sporangiophores in simple or lax 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
with external proliferationexternal proliferation:
formation of a sporangium after a sporangiophore has emerged from beneath and external to an empty sporangium that has previously emitted its zoospores (cf. internal proliferation)
. Hyphal swellings ellipsoid, but rare. 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 smooth-walled, often with a tapering base and long stalks, average size 31.2 ± 3.2 mm (20.9–41.5 µm). OosporesOospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
are both pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
and 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
, turning golden-brown on maturity, average size 27.4 ± 3.3 µm (17.9–37.8). AntheridiaAntheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
 are paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
.

Most typical characters

The most distinguishing feature of Phytopthora elongata are the unusually elongated 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
after which it is named.

Specimen(s) evaluated

Australia; Western Australia, Dwellingup, from rhizosphere soil of dying Eucalyptus marginata, April 2004, M. Stukely, CBS 125799 = VHS 13482; VHS 13615; VHS 15078; VHS 13559; VHS 13663; from rhizosphere soil of Leucopogon propinquus, VHS 7134; Bridgetown, from rhizosphere soil of Patersonia xanthina, 1999, VHS 6362; Pemberton, from rhizosphere soil of Banksia grandis, 2006, VHS 16103

WPC = P19596, CPHST BL 62

Hosts and distribution

Distribution Australia (Western Australia and Victoria)
Substrate: roots, collars, and rhizosphere soil
Disease note: wilting, dieback
Hosts: numerous; including Eucalyptus marginata, Corymbia calophylla, Banksia grandis, Leucopogon propinquus, Dryandra squarrosa, Xanthorrhoea preissii, X. gracilis and Patersonia xanthina; wide host range

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional info: pathogenic toward Eucalyptus marginata and Banksia grandis

Additional references and links

 

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

 

• Google All Phytophthora elongata
• Google Images Phytophthora elongata
• Google Scholar Phytophthora elongata

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.