Name and publication

Phytophthora macrochlamydospora J.A.G. Irwin (1991)

Irwin JAG. 1991. Phytophthora macrochlamydospora, a new species from Australia. Mycologia 83: 517–519.

Nomenclature

Mycobank

MB355271

Typification

from Irwin (1991)

Type: AUSTRALIA, from soybean (Glycine max), collected Indooroopilly, Queensland, collected in 13 Feb. 1974, J. A. G. Holotypus BRIP 17047.

Ex-type: Irwin 20502

NOTE: Irwin 20502 deposited WPC P10263.

Ex-type in other collections

(ET) WPC P10263, S&T BL 71 (Abad), Irwin 20502, DP1 20502 (CRCTPP), UQ205 

Molecular identification

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

Phytophthora macrochlamydospora isolate CPHST BL 71 (= P10263 WPC) = ITS rDNA MG865528, COI MH136923

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 macrochlamydospora CPHST BL 71
• NCBI: Phytophthora macrochlamydospora P10263
• EPPO-Q-bank: Phytophthora macrochlamydospora
• BOLDSYSTEMS: Phytophthora macrochlamydospora (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
9c

Genome sequence

Phytophthora macrochlamydospora strain ex-type BL 71. Accession genome USDA_Pmac_71_1.0, BioProject PRJNA612532, USDA APHIS PPQ S&T 2020

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 after 7 days of growth on potato dextrose agar and malt extract agar with chrysanthemum pattern, and on V8 agar with light chrysanthemum pattern. Minimum temperature for growth is 6°C, optimum 23–30°C, and maximum 34°C. 

Conditions for growth and sporulation

Hyphal swellings and 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
produced in solid and liquid 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
nonpapillatenonpapillate:
pertaining to the production of a non-distinct, or inconspicuous, papilla at the distal end of the sporangium (cf. papillate and semipapillate)
and 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)
; 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)
(20–50 L x 18–36 W µm); showing internal proliferationinternal proliferation:
internal proliferation occurs when the sporangiophore continues to grow through an empty sporangium
; originated on unbranched sporangiophores up to 500 µm long. Hyphal swellings spherical to 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
, catenulatecatenulate:
having a chain-like form
or solitary. 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
spherical (28–84 µm diam), terminal or intercalaryintercalary:
positioned within a hypha (cf. terminal)
.

Sexual phase

Sterile.

Most typical characters

Phytophthora machrochlamydospora is characterized by the production of abundant thick-walled 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
, catenulated globoseglobose:
having a rounded form resembling that of a sphere
to elongated hyphal swellings, and the sterile condition of the sexual stage of the species.

Specimen(s) evaluated

Phytophthora macrochlamydospora ex-type CPHST BL 71, duplicate of P10263 (World Phytophthora Collection), which is a duplicate of Irwin 20502

Hosts and distribution

Distribution: Australia
Substrate: stems, roots
Disease note: stem and root rot
Host: Glycine max (soybean, Fabaceae)

Retrieved January 31, 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.).

Additional references and links

 

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

 

• Google All Phytophthora macrochlamydospora
• Google Images Phytophthora macrochlamydospora
• Google Scholar Phytophthora macrochlamydospora

Fact sheet author

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