Name and publication

Phytophthora quercetorum Y. Balci & S. Balci (2008)

Balci Y, Balci S, Blair JE, Park SY, Kang S, and MacDonald WL. 2008. Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central U.S. oak forests. Mycological Research 112: 906–916 (pp. 911).

Corresponding author: yibalci@mail.wvu.edu Yilmaz.Balci@aphis.usda.gov

Nomenclature

from Balci et al. (2008)

Mycobank

MB510683

Etymology

refers to oak forests

Typification

Type: UNITED STATES OF AMERICA, isolated from the rhizosphere soil of oak (Quercus rubra), by Y. Balci in Maryland, Townhill, during July 2004; holotype: BPI 878357 (dry culture deposited to the Herbarium BPI of the Systematic Mycology and Microbiology Laboratory in MD, USA)

Ex-type: CBS 121119 and ATCC MYA-4186 (living cultures)

Sequences for ex-type in original manuscript: P15555 (WPC) = 60S Ribosomal protein L10 EU080900, β-tubulin EU080901, elongation factor 1 alpha EU080902, Enolase EU080903, Heat shock protein 90 EU080904, 28S Ribosomal DNA EU080905, TigA gene fusion EU080906

Ex-type in other collections

(ET) CBS 121119, ATCC MYA-4186, NRRL 64164, WPC P15555, S&T BL 52G (Abad)

Molecular identification

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

Phytophthora quercetorum isolate CPHST BL 52G (= P15555 WPC) = ITS rDNA MG865577, COI MH136969

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 quercetorum CPHST BL 52G
• NCBI: Phytophthora quercetorum P15555
• EPPO-Q-bank: Phytophthora quercetorum CBS 121119
• BOLDSYSTEMS: Phytophthora quercetorum (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
4

Morphological identification

adapted from Balci et al. (2008)

Colonies and cardinal temperatures

Colony colony:
assemblage of hyphae which usually develops form a single source and grows in a coordinated way
morphology on PDA, MEA with rosette chrysanthemum pattern. Minimum growth temperature 9°C, optimum 18–24°C, and maximum 30°C.

Conditions for growth and sporulation

Sporangia occasionally produced on culture media and abundantly produced on agar plugs immersed in soil extract water. GametangiaGametangia:
part of hypha specialized for fusion in sexual reproduction (see antheridium and oogonium)
abundantly produced in culture media. 

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
papillatepapillate:
pertaining to the production of a distinct papilla at the distal end of the sporangium (cf. nonpapillate and semipapillate)
and occasionally bipapillate; persistentpersistent:
pertaining to sporangia that remain attached to the sporangiophore and do not separate or detach easily (cf. caducous)
; ovoidovoid:
egg-shaped, with the widest part at the base of the sporangium and the narrow part at the apex
, elongated, or distorted shapes (25–44 L x 18–33 W µm) originated in unbranched and simple sympodial sporangiophores or intercalaryintercalary:
positioned within a hypha (cf. terminal)
in hyphaehyphae:
single, tubular filament of a fungal or oomycete thallus; the basic structural unit of a fungus or oomycete
. Sporangiophores with basal or intercalaryintercalary:
positioned within a hypha (cf. terminal)
swellings. Hyphal swellings are not observed but hyphaehyphae:
single, tubular filament of a fungal or oomycete thallus; the basic structural unit of a fungus or oomycete
often present coralloid appearance. 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
rarely observed and are globoseglobose:
having a rounded form resembling that of a sphere
and subglobose.

Sexual phase

Homothallichomothallic:
pertaining to sexual reproduction that can take place within a single thallus (i.e. self-fertile, non-outcrossing) (cf. heterothallic).
. OogoniaOogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
smooth-walled, globoseglobose:
having a rounded form resembling that of a sphere
(17–40 µm), frequently with comma-shaped tapered basetapered base:
pertaining to the base of a sporangium or oogonium; funnel-shaped
on oogonial hyphae; antheridiaantheridia:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
paragynousparagynous:
pertaining to the sexual stage in which the antheridium is attached to the side of the oogonium (cf. amphigynous)
, cylindrical or club-shaped; oopores 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)
or slightly 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)
(14–33 µm).

Most typical characters

Phytophthora quercetorum is characterized by the presence of oogoniaoogonia:
the female gametangium in which the oospore forms after fertilization by the antheridium
frequently with comma-shaped tapered basetapered base:
pertaining to the base of a sporangium or oogonium; funnel-shaped
and the shape and origin of the 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
.

Additional specimen(s) evaluated

Phytophthora quercetorum ex-type CPHST BL 52G, duplicate of P15555 (World Phytophthora Collection)

Hosts and distribution

Distribution: North America (USA), Europe
Substrate: soil, rhizosphere
Host: Quercus alba (Fagaceae), Acer rubrum (Sapindaceae), Hedera helix (Araliaceae), Quercus robur

Retrieved February 01, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

 

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

 

• Google All Phytophthora quercetorum
• Google Images Phytophthora quercetorum
• Google Scholar Phytophthora quercetorum

Fact sheet author

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