Phytophthora quercina

Name and publication

Phytophthora quercina Jung (1999)

Jung T, Cooke DEL, Blaschke H, Duncan JM, and Oswald W. 1999. Phytophthora quercina sp. nov., causing root rot of European oaks. Mycol. Res. 103:785–798.

Nomenclature

from Jung et al. (1999)

Mycobank

MB460046

Etymology

derived from its original host, Quercus spp.

Typification

Type: GERMANY, near Munich, isolated from rhizosphere soil containing necrotic roots of mature declining oak (Quercus robur L.) in Südbayern in May 1995, isolate QUE 3

Ex-type: CBS 784.95 = no. Hag 4 (= QUE 3), deposited by T. Jung LMU, Dec. 1995

Ex-type in other collections

CBS 784.95 = (IFB-QUE3) = P10439 (WOC/WPC), CPHST BL 110 (Abad), MYA-4084, p290, 30A5 (Yang)

Molecular identification

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

Phytophthora quercina ex-type isolate CPHST BL 110 (= P10439 WPC) = ITS rDNA MG865578, COI MH136970

Phytophthora quercina selected specimen isolate CPHST BL 53G (= P10334 WPC) = ITS rDNA MG865579, COI MH136971

Sequences for ex-type in other sources
Position in ITS phylogenetic tree

Clade 3b

Morphological identification

adapted from Jung et al. (1999)

Colonies and cardinal temperatures

Colony morphology on PDA, MEA with non-distinct pattern. Minimum growth temperature 3°C, optimum 21°C, and maximum 24°C.

Conditions for growth and sporulation

Sporangia produced in small numbers on solid agar and abundantly in liquid culture. Oogonia form readily in single culture.

Asexual phase

Sporangia papillate or occasionally bipapillate; persistent; ovoid, obpyriform, elongate, globose (25–61 L x 18–36 W µm) sometimes with elongated necks; no internal proliferation is observed, originated in unbranched or simple sympodial sporangiophores. Hyphal swellings globose, subglobose, elongate, with some radiating hyphae, some produced individually and some in chains. Chlamydospores absent. Jung et al. (1999) reported the ocurrence of chlamydospores on MEA for some isolates.

Sexual phase

Homothallic. Oogonia smooth-walled, spherical, ovoid to elongate, and ellipsoid (22–49 µm); antheridia paragynous, spherical, club-shaped to irregular, usually inserted near the oogonial stalk; oospores aplerotic and some plerotic (17–44 µm) and thick-walled (2.5 µm). Older oospore walls often turn golden-yellow.

Most typical characters

Phytophthora quercina is characterized by the presence of elongated, ellipsoid oogonia that contain the same shape of oospores.

Additional specimen(s) evaluated

Phytophthora quercina ex-type CPHST BL 110, duplicate of P10439 (World Phytophthora Collection)

selected specimen CPHST BL 53G = P10334 (WPC)

Hosts and distribution

Distribution: Asia (Turkey), Europe (Germany, Hungary, Italy, Sweden); recently reported from soil under declining oak trees in USA (MO)
Substrate: roots, rhizosphere soil
Disease note: implicated in oak decline, associated with various other Phytophthora spp
Host: Quercus spp. (Fagaceae)

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

Quarantine status

USA: This species was listed as a species of concern during the 2009 Phytophthora prioritization project conducted by USDA APHIS PPQ CPHST PERAL (Schwartzburg et al.).

Phytophthora quercina is also listed in the U.S. Regulated Plant Pest Table (last modified Nov. 15, 2017).

EU: no EU status; council directive 01.13.2010 (Q-bank, June 2018)

EPPO: no EPPO status, version 09.30.2011 (Q-bank, June 2018)

Additional references and links

Cooke DE, Jung T, Williams N, Shubbert R, Bahweg G, Oûwald W, and Duncan JM. 1999. Molecular evidence supports Phytophthora quercina as a distinct species. Mycol. Res. 103: 799–804.

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America