Name and publication

Phytophthora pachypleura Henricot, Pérez Sierra & T. Jung (2014)

Henricot B, Pérez Sierra A, and Jung T. 2014. Phytophthora pachypleura sp. nov., a new species causing root rot of Aucuba japonica and other ornamentals in the United Kingdom. Plant Pathology 63: 1095–1109.

Corresponding author: beatricehenricot@rhs.org.uk, beatrice.henricot@forestry.gsi.gov.uk

Nomenclature

from Henricot et al. (2014)

MycoBank

MB570084

Fungal names

FN570084

Etymology

refers to the thick wall of the oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
(‘pachy’ = ‘thick’ and ‘pleura’ = ‘wall’ in Greek)

Typification

Type: UNITED KINGDOM, Cheshire, isolated from roots of Aucuba japonica, June 2008, B. Henricot; holotype IMI 502404 (preserved in a metabolically inactive state by deep-freezing in CABI, Egham, Surrey, UK)

Ex-type: culture IMI 502404

NOTE: Phytophthora pachypleura IMI 502404 not available at HerbIMI (1/28/2017)

Sequences for ex-type in original manuscript

Phytophthora sp. BH-2013 strain RHS 53593.1 = ITSrDNA KC855330, β-tub KC855354, TEF KC855378, Cox1 KC855426, NDH KC855402

Ex-type in other collections

(ET) CABI IMI502404 (AVA), WPC P19987, S&T BL 146 (Abad), 61H7 (Hong), TJ 0472 (Jung)

Molecular identification

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

Phytophthora pachypleura isolate CPHST BL 146 (= P19987 WPC) = ITS rDNA MG865558, COI MH136948

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 pachypleura CPHST BL 146 
• NCBI: Phytophthora sp. 1 BH-2013 strain RHS 53593.1
• EPPO-Q-bank: Phytophthora pachypleura
• BOLDSYSTEMS: Phytophthora pachypleura (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
2c

Morphological identification

adapted from Henricot et al. (2014)

Colonies and cardinal temperatures

Colonies on V-8 agar, potato dextrose agar, and malt extract agar with chrysanthemum pattern. Minimum temperature for growth 5°C, optimum 25°C, maximum 35°C.

Conditions for growth and sporulation

Sporangia produced abundantly on non-sterile soil extract, and gametangiagametangia:
part of hypha specialized for fusion in sexual reproduction (see antheridium and oogonium)
readily produced on V8A within 7 days.

Asexual phase

Sporangia semipapillate, sometimes 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
, ellipsoidellipsoid:
refers to a solid body that forms an ellipse in the longitudinal plane and a circle in cross section; many fungal spores are ellipsoidal or elliptic
, obpyriformobpyriform:
inversely pear-shaped, i.e. with the widest part at the point of attachment (cf. pyriform)
, limoniform, and with irregular or distorted shapes (mouse-shaped) (30–84 L x 22–44 W µm); showing 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)
close to the sporangial base resulting in loose 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
or originated in unbranched sporangiophores. Hyphal swellings sometimes formed close to the sporangial base. 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
smooth-walled, globoseglobose:
having a rounded form resembling that of a sphere
to slightly subglobose (21–39 µm diam.), sometimes with tapering base; 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)
, obovoidobovoid:
inversely egg-shaped; ovoid, but with the widest part at the apex
, club-shaped, or irregular, usually attached close to the oogonial stalk and in some cases more than one antheridiumantheridium:
the male gametangium; a multinucleate, swollen hyphal tip affixed firmly to the wall of the female gametangium (the oogonium)
per oogoniumoogonium:
the female gametangium in which the oospore forms after fertilization by the antheridium
is observed; oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
predominantly pleroticplerotic:
pertaining to an oospore that fills the oogonium (cf. aplerotic)
and sometimes 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)
(17–30 µm diam.); oosporesoospores:
zygote or thick-walled spore that forms within the oogonium after fertilization by the antheridium; may be long-lived
wall thick.

Additional specimen(s) evaluated

Phytophthora pachypleura ex-type CPHST BL 146, duplicate of P19987 (World Phytophthora Collection)

Hosts and distribution

Distribution: Europe (Italy, UK)
Substrate: roots
Disease note: root rot
Host: Aucuba japonica (Garryaceae)

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

Additional references and links

 

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

 

• Google All Phytophthora pachypleura
• Google Images Phytophthora pachypleura
• Google Scholar Phytophthora pachypleura

Fact sheet author

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